View source for Median lethal dose

{{Short description|Measurement of lethal dose of substance}}
{{redirect|LD50}}
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In [[toxicology]], the '''median lethal dose''', '''LD<sub>50</sub>''' (abbreviation for "[[lethal dose]], 50%"), '''LC<sub>50</sub>''' (lethal concentration, 50%) or '''LCt<sub>50</sub>''' is a [[toxic unit]] that measures the [[lethal dose]] of a given [[Chemical substance|substance]].<ref>{{Cite web|url=https://goldbook.iupac.org/html/A/A00025.html|work=IUPAC Gold Book|title=Absolute lethal dose (LD100)|publisher=International Union of Pure and Applied Chemistry|language=en|access-date=2019-07-01|archive-url=https://web.archive.org/web/20190701134347/https://goldbook.iupac.org/html/A/A00025.html|archive-date=2019-07-01|url-status=dead}}</ref> The value of LD<sub>50</sub> for a substance is the [[Dose (pharmacology)|dose]] required to kill half the members of a tested population after a specified test duration. LD<sub>50</sub> figures are frequently used as a general indicator of a substance's [[acute toxicity]]. A lower LD<sub>50</sub> is indicative of higher toxicity.

The term LD<sub>50</sub> is generally attributed to John William Trevan.<ref name="Biographical Memoirs of Fellows of the Royal Society 1957 pp. 273–288">{{cite journal | title=John William Trevan, 1887-1956 | journal=Biographical Memoirs of Fellows of the Royal Society | volume=3 | date=1957 | issn=0080-4606 | doi=10.1098/rsbm.1957.0019 | pages=273–288 | url=https://royalsocietypublishing.org/doi/pdf/10.1098/rsbm.1957.0019 | access-date=2024-03-31 | archive-date=2020-03-28 | archive-url=https://web.archive.org/web/20200328170611/https://royalsocietypublishing.org/doi/pdf/10.1098/rsbm.1957.0019 | url-status=live | url-access=subscription }}</ref> The test was created by J. W. Trevan in 1927.<ref>{{cite web|url=http://www.ccohs.ca/oshanswers/chemicals/ld50.html|title=What is a LD50 and LC50?|work=OSH Answers Fact Sheets|date=5 October 2021|publisher=Canadian Centre for Occupational Health and Safety|access-date=15 July 2006|archive-date=26 June 2015|archive-url=https://web.archive.org/web/20150626013647/http://www.ccohs.ca/oshanswers/chemicals/ld50.html|url-status=live}}</ref> The term '''semilethal dose''' is occasionally used in the same sense, in particular with translations of foreign language text, but can also refer to a sublethal dose. LD<sub>50</sub> is usually determined by tests on animals such as [[Laboratory mouse|laboratory mice]]. In 2011, the U.S. [[Food and Drug Administration]] approved alternative methods to LD<sub>50</sub> for testing the cosmetic drug [[botox]] without animal tests.<ref>{{cite web
 |date=24 June 2011 
 |title=Allergan Receives FDA Approval for First-of-Its-Kind, Fully in vitro, Cell-Based Assay for BOTOX and BOTOX Cosmetic (onabotulinumtoxinA) 
 |publisher=Allergan Web site 
 |url=http://agn.client.shareholder.com/releasedetail.cfm?ReleaseID=587234 
 |access-date=2012-08-15 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20110626185759/http://agn.client.shareholder.com/releasedetail.cfm?ReleaseID=587234 
 |archive-date=26 June 2011 
}}</ref><ref>{{cite news | vauthors = Gaul GM | date = 12 April 2008 | title = In U.S., Few Alternatives To Testing On Animals | newspaper = [[Washington Post]] | url = https://www.washingtonpost.com/wp-dyn/content/article/2008/04/11/AR2008041103733.html | access-date = 2011-06-26 | archive-date = 2012-11-12 | archive-url = https://web.archive.org/web/20121112163835/http://www.washingtonpost.com/wp-dyn/content/article/2008/04/11/AR2008041103733.html | url-status = live }}</ref>

== Conventions ==
The LD<sub>50</sub> is usually expressed as the mass of substance administered per unit mass of test subject, typically as [[milligram]]s of substance per [[kilogram]] of body mass, sometimes also stated as [[nanogram]]s (suitable for [[botulinum toxin]]), [[microgram]]s, or [[gram]]s (suitable for [[paracetamol]]) per kilogram. Stating it this way allows the relative toxicity of different substances to be compared and normalizes for the variation in the size of the animals exposed (although toxicity does not always scale simply with body mass). For substances in the environment, such as poisonous vapors or substances in water that are toxic to fish, the concentration in the environment (per cubic metre or per litre) is used, giving a value of LC<sub>50</sub>. But in this case, the exposure time is important (see below).

The choice of 50% lethality as a benchmark avoids the potential for ambiguity of making measurements in the extremes and reduces the amount of testing required. However, this also means that LD<sub>50</sub> is not the lethal dose for all subjects; some may be killed by much less, while others survive doses far higher than the LD<sub>50</sub>. Measures such as "LD<sub>1</sub>" and "LD<sub>99</sub>" (dosage required to kill 1% or 99%, respectively, of the test population) are occasionally used for specific purposes.<ref>{{cite web|editor=Doris V. Sweet|date=July 1997|url=https://www.cdc.gov/niosh/pdfs/97-119-a.pdf|title=Registry of Toxic Effects of Chemical Substances (RTECS) / Comprehensive Guide to the RTECS|publisher=U.S. Department of Health and Human Services|url-status=dead|archive-url=https://web.archive.org/web/20130516165953/http://www.cdc.gov/niosh/pdfs/97-119-a.pdf|archive-date=2013-05-16 |id=DHHS (NIOSH) Publication No. 97-119}}</ref>

Lethal dosage often varies depending on the method of [[Drug administration|administration]]; for instance, many substances are less toxic when administered orally than when [[Intravenous therapy|intravenously]] administered. For this reason, LD<sub>50</sub> figures are often qualified with the mode of administration, e.g., "LD<sub>50</sub> i.v."

The related quantities LD<sub>50</sub>/30 or LD<sub>50</sub>/60 are used to refer to a dose that without treatment will be lethal to 50% of the population within (respectively) 30 or 60 days. These measures are used more commonly within radiation [[health physics]], for [[ionizing radiation]], as survival beyond 60 days usually results in recovery.

A comparable measurement is LCt<sub>50</sub>, which relates to lethal dosage from exposure, where C is concentration and t is time. It is often expressed in terms of mg-min/m<sup>3</sup>. ICt<span style="font-size:100%;"><sub>50</sub></span> is the dose that will cause incapacitation rather than death. These measures are commonly used to indicate the comparative efficacy of [[chemical warfare]] agents, and dosages are typically qualified by rates of breathing (e.g., resting = 10&nbsp;L/min) for inhalation, or degree of clothing for skin penetration. The concept of Ct was first proposed by [[Fritz Haber]] and is sometimes referred to as [[Haber's law]], which assumes that exposure to 1 minute of 100&nbsp;mg/m<sup>3</sup> is equivalent to 10 minutes of 10&nbsp;mg/m<sup>3</sup> (1 × 100 = 100, as does 10 × 10 = 100).

Some chemicals, such as [[hydrogen cyanide]], are rapidly detoxified by the human body, and do not follow Haber's law. In these cases, the lethal concentration may be given simply as LC<sub>50</sub> and qualified by a duration of exposure (e.g., 10 minutes). The [[Material safety data sheet|material safety data sheets]] for toxic substances frequently use this form of the term even if the substance does follow Haber's law.

For disease-causing organisms, there is also a measure known as the median infective dose and dosage. The median infective dose (ID<sub>50</sub>) is the number of organisms received by a person or test animal qualified by the route of administration (e.g., 1,200 org/man per oral). Because of the difficulties in counting actual organisms in a dose, infective doses may be expressed in terms of biological assay, such as the number of LD<sub>50</sub>s to some test animal. In [[biological warfare]] infective dosage is the number of infective doses per cubic metre of air times the number of minutes of exposure (e.g., ICt<sub>50</sub> is 100 medium doses - min/m<sup>3</sup>).

== Limitation ==
As a measure of toxicity, LD<sub>50</sub> is somewhat unreliable and results may vary greatly between testing facilities due to factors such as the genetic characteristics of the sample population, animal species tested, environmental factors and mode of administration.<ref name="ReferenceA">Ernest Hodgson (2004). ''A Textbook of Modern Toxicology''. Wiley-Interscience (3rd ed.).{{page needed|date=January 2014}}</ref>

There can be wide variability between species as well; what is relatively safe for rats may very well be extremely toxic for humans (''[[cf.]]'' [[paracetamol toxicity]]), and vice versa. For example, chocolate, comparatively harmless to humans, is known to be [[Health effects of chocolate#Non-human animals|toxic to many animals]]. When used to test [[venom]] from venomous creatures, such as [[snake]]s, LD<sub>50</sub> results may be misleading due to the physiological differences between mice, rats, and humans. Many [[venomous snake]]s are specialized predators on mice, and their venom may be adapted specifically to incapacitate mice; and [[mongoose]]s may be exceptionally resistant. While most [[mammal]]s have a very similar physiology, LD<sub>50</sub> results may or may not have equal bearing upon every mammal species, such as humans, etc.

== Examples ==
Note: Comparing substances (especially drugs) to each other by LD<sub>50</sub> can be misleading in many cases due (in part) to differences in [[Effective dose (pharmacology)|effective dose]] (ED<sub>50</sub>). Therefore, it is more useful to compare such substances by [[therapeutic index]], which is simply the ratio of LD<sub>50</sub> to ED<sub>50</sub>.<ref>{{Cite web |date=2011-01-26 |title=Therapeutic index {{!}} CME at Pharmacology Corner |url=https://pharmacologycorner.com/therapeutic-index/ |access-date=2024-07-15 |website=pharmacologycorner.com |language=en-US}}</ref>

The following examples are listed in reference to LD<sub>50</sub> values, in descending order, and accompanied by LC<sub>50</sub> values, {bracketed}, when appropriate.

{| class="wikitable sortable"
|-wa
! Substance
! Animal, route
! class=unsortable| LD<sub>50</sub> <br /> {LC<sub>50</sub>} <br />
! data-sort-type="number"| LD<sub>50</sub> : g/kg <br /> {LC<sub>50</sub> : g/L} <br /> standardised
! class=unsortable| Reference
|-
| [[Water intoxication|Water]] ({{chem2|H2O}})
| rat, oral
| >{{ntsh|90000}}90,000&nbsp;mg/kg
| >90
| <ref>{{cite web|url=http://www.sciencelab.com/msds.php?msdsId=9927321 |title=Material Safety Data Sheet Water MSDS |at=Section 11: Toxicological Information for the LD<sub>50</sub> verification |access-date=2012-05-09 |archive-url=https://web.archive.org/web/20120902122244/http://www.sciencelab.com/msds.php?msdsId=9927321 |archive-date=2012-09-02 |url-status=dead }}</ref>
|-
| [[Sucrose]] (table sugar)
| rat, oral
| {{ntsh|29700}}29,700&nbsp;mg/kg
| 29.7
| <ref>{{cite web|url=http://msds.chem.ox.ac.uk/SU/sucrose.html|title=Safety (MSDS) data for sucrose|url-status=dead|archive-url=https://web.archive.org/web/20110612032043/http://msds.chem.ox.ac.uk/SU/sucrose.html|archive-date=2011-06-12|website=ox.ac.uk}}</ref>
|-
| [[Corn syrup]]
| rat, oral
| {{ntsh|25800}}25,800&nbsp;mg/kg
| 25.8
| <ref>{{cite web|url=https://www.fishersci.com/store/msds?partNumber=S25339&productDescription=fisher-science-educationtrade-corn-syrup&vendorId=VN00115888&keyword=true&countryCode=US&language=en|title=Safety (MSDS) data for Corn Syrup|website=fishersci.com|access-date=2022-09-21|archive-date=2022-09-21|archive-url=https://web.archive.org/web/20220921201129/https://www.fishersci.com/store/msds?partNumber=S25339&productDescription=fisher-science-educationtrade-corn-syrup&vendorId=VN00115888&keyword=true&countryCode=US&language=en|url-status=live}}</ref>
|-
| [[Glucose]] (blood sugar)
| rat, oral
| {{ntsh|25800}}25,800&nbsp;mg/kg
| 25.8
| <ref>{{cite web|url=http://www.chem.utoronto.ca/~pmeindl/labs/msds%20files/glucose.pdf|title=Safety (MSDS) data for glucose|website=utoronto.ca|access-date=2016-12-31|archive-url=https://web.archive.org/web/20170101003021/http://www.chem.utoronto.ca/~pmeindl/labs/msds%20files/glucose.pdf|archive-date=2017-01-01|url-status=dead}}</ref>
|-
| [[Monosodium glutamate]] (MSG)
| rat, oral
| {{ntsh|16600}}16,600&nbsp;mg/kg
| 16.6
| <ref name="Walker00">{{cite journal | vauthors = Walker R, Lupien JR | title = The safety evaluation of monosodium glutamate | journal = The Journal of Nutrition | volume = 130 | issue = 4S Suppl | pages = 1049S–1052S | date = April 2000 | pmid = 10736380 | doi = 10.1093/jn/130.4.1049S | doi-access = free }}</ref>
|-
| [[Stevioside]] (from [[stevia]])
| mice and rats, oral
| {{ntsh|15000}}15,000&nbsp;mg/kg
| 15
| <ref>{{cite journal | vauthors = Toskulkao C, Chaturat L, Temcharoen P, Glinsukon T | title = Acute toxicity of stevioside, a natural sweetener, and its metabolite, steviol, in several animal species | journal = Drug and Chemical Toxicology | volume = 20 | issue = 1–2 | pages = 31–44 | year = 1997 | pmid = 9183561 | doi = 10.3109/01480549709011077 }}</ref>
|-
| [[Gasoline]] (petrol)
| rat
| {{ntsh|14063}}14,063&nbsp;mg/kg
| 14.0
| <ref>{{cite web | url=https://www.atsdr.cdc.gov/toxprofiles/tp72.pdf | title=Toxicological profile for gasoline | date=June 1995 | publisher=U.S. Department of Health and Human Services, Public Health Service Agency for Toxic Substances and Disease Registry | pages=47 | access-date=2020-01-05 | archive-url=https://web.archive.org/web/20170515140517/https://www.atsdr.cdc.gov/toxprofiles/tp72.pdf | archive-date=2017-05-15 | url-status=dead }}</ref>
|-
| [[Vitamin C]] (ascorbic acid)
| rat, oral
| {{ntsh|11900}}11,900&nbsp;mg/kg
| 11.9
| <ref>{{cite web|url=http://physchem.ox.ac.uk/MSDS/AS/ascorbic_acid.html |archive-url=https://archive.today/20070209221915/http://physchem.ox.ac.uk/MSDS/AS/ascorbic_acid.html |url-status=dead |archive-date=2007-02-09 |title=Safety (MSDS) data for ascorbic acid |access-date=2007-02-21 |date=2005-10-09 |publisher=[[Oxford University]] }}</ref>
|-
| [[Glyphosate]] (isopropylamine salt)
| rat, oral
| {{ntsh|10537}}10,537&nbsp;mg/kg
| 10.537
| <ref>{{cite web|url=https://pubchem.ncbi.nlm.nih.gov/compound/38078#section=Non-Human-Toxicity-Values|title=Glyphosate-isopropylammonium|website=PubChem|access-date=2019-01-17|archive-date=2021-03-02|archive-url=https://web.archive.org/web/20210302061538/https://pubchem.ncbi.nlm.nih.gov/compound/38078#section=Non-Human-Toxicity-Values|url-status=live}}</ref>
|-
| [[Lactose]] (milk sugar)
| rat, oral
| {{ntsh|10000}}10,000&nbsp;mg/kg
| 10
| <ref>{{cite web|url=http://www.sciencestuff.com/msds/C1958.pdf|title=Safety (MSDS) data for Lactose|access-date=2016-12-31|archive-url=https://web.archive.org/web/20160803150146/http://www.sciencestuff.com/msds/C1958.pdf|archive-date=2016-08-03|url-status=dead}}</ref>
|-
| [[Aspartame]]
| mice, oral
| {{ntsh|10000}}10,000&nbsp;mg/kg
| 10
| <ref>{{cite web|url=https://www.spectrumchemical.com/MSDS/A6051.pdf|archive-url=https://web.archive.org/web/20161226221445/https://www.spectrumchemical.com/MSDS/A6051.pdf|url-status=dead|archive-date=2016-12-26|title=Material Safety Data Sheet: Aspartame|publisher=Spectrum}}</ref>
|-
| [[Urea]] ({{chem2|OC(NH2)2}})
| rat, oral
| {{ntsh|8471}}8,471&nbsp;mg/kg
| 8.471
| <ref>{{cite web |url=http://www.sciencelab.com/msds.php?msdsId=9927317 |title=Safety (MSDS) data for urea |access-date=2015-03-06 |date=2015-03-06 |at=Section 11: Toxicological Information for the LD<sub>50</sub> verification |archive-url=https://web.archive.org/web/20150301225811/http://www.sciencelab.com/msds.php?msdsId=9927317 |archive-date=2015-03-01 |url-status=dead }}</ref>
|-
| [[Cyanuric acid]]
| rat, oral
| {{ntsh|7700}}7,700&nbsp;mg/kg
| 7.7
| <ref name="Babayan">A.A. Babayan, A.V.Aleksandryan, "Toxicological characteristics of melamine cyanurate, melamine and cyanuric acid", Zhurnal Eksperimental'noi i Klinicheskoi Meditsiny, Vol.25, 345–9 (1985). Original article in Russian.</ref>
|-
| [[Cadmium sulfide]] (CdS)
| rat, oral
| {{ntsh|7080}}7,080&nbsp;mg/kg
| 7.08
| <ref>[http://www.alfa.com/content/msds/german/A14544.pdf Advanced Search – Alfa Aesar – A Johnson Matthey Company] {{Webarchive|url=https://web.archive.org/web/20150724053453/http://www.alfa.com/content/msds/german/A14544.pdf |date=2015-07-24 }}. Alfa.com. Retrieved on 2013-07-17.</ref>
|-
| [[Ethanol]] ({{chem2|CH3CH2OH}})
| rat, oral
| {{ntsh|7060}}7,060&nbsp;mg/kg
| 7.06
| <ref>{{cite web|url=http://msds.chem.ox.ac.uk/ET/ethyl_alcohol.html|title=Safety (MSDS) data for ethyl alcohol|url-status=dead|archive-url=https://web.archive.org/web/20110714040451/http://msds.chem.ox.ac.uk/ET/ethyl_alcohol.html|archive-date=2011-07-14|website=ox.ac.uk}}</ref>
|-
| Sodium [[Sarin#Production and structure|isopropyl methylphosphonic acid]] (IMPA, metabolite of [[sarin]])
| rat, oral
| {{ntsh|6860}}6,860&nbsp;mg/kg
| 6.86
| <ref>{{Cite report|title=Mammalian Toxological Evaluation of DIMP and DCBP (Phase 3 – IMPA)|type=Final report| vauthors = Mecler FJ |date=May 1981|publisher=Litton Bionetics, Inc.|quote=The oral LD50 values for the test material, IMPA, were 7650 and 6070 mg/kg for male and female rats, respectively.|url=http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA107574|archive-url=https://web.archive.org/web/20131004070929/http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA107574|url-status=dead|archive-date=October 4, 2013}}</ref>
|-
| [[Melamine]]
| rat, oral
| {{ntsh|6000}}6,000&nbsp;mg/kg
| 6
| <ref name="Babayan" />
|-
| [[Taurine]]
| rat, oral
| {{ntsh|5000}}5,000&nbsp;mg/kg
| 5
| <ref>{{cite web|url=http://datasheets.scbt.com/sc-202354.pdf|title=Safety data for taurine|website=scbt.com|access-date=2017-01-18|archive-url=https://web.archive.org/web/20170118214915/http://datasheets.scbt.com/sc-202354.pdf|archive-date=2017-01-18|url-status=dead}}</ref>
|-
| [[Melamine cyanurate]]
| rat, oral
| {{ntsh|4100}}4,100&nbsp;mg/kg
| 4.1
| <ref name="Babayan" />
|-
| [[Fructose]] (fruit sugar)
| rat, oral
| 4,000&nbsp;mg/kg
| 4
| <ref>{{cite web|url=https://www.sciencelab.com/msds.php?msdsId=9927537|title=Safety (MSDS) data for fructose|website=sciencelab.com|access-date=2016-12-31|archive-url=https://web.archive.org/web/20170702044942/http://www.sciencelab.com/msds.php?msdsId=9927537|archive-date=2017-07-02|url-status=dead}}</ref>
|-
| [[Sodium molybdate]] ({{chem2|Na2MoO4}})
| rat, oral
| 4,000&nbsp;mg/kg
| 4
| <ref>{{cite web|url=http://msds.chem.ox.ac.uk/SO/sodium_molybdate.html|title=Safety (MSDS) data for sodium molybdate|url-status=dead|archive-url=https://web.archive.org/web/20110128034147/http://msds.chem.ox.ac.uk/SO/sodium_molybdate.html|archive-date=2011-01-28|website=ox.ac.uk}}</ref>
|-
| [[Salt poisoning|Sodium chloride]] (table salt)
| rat, oral
| 3,000&nbsp;mg/kg
| 3
| <ref>{{cite web|url=http://msds.chem.ox.ac.uk/MSDS/SO/sodium_chloride.html|title=Safety (MSDS) data for sodium chloride|url-status=dead|archive-url=https://web.archive.org/web/20110607224738/http://msds.chem.ox.ac.uk/SO/sodium_chloride.html|archive-date=2011-06-07|website=ox.ac.uk}}</ref>
|-
| [[Paracetamol poisoning|Paracetamol]] (acetaminophen)
| rat, oral
| 2000&nbsp;mg/kg
| 2
| <ref>{{cite web|url=http://msds.chem.ox.ac.uk/AC/acetylsalicylic_acid.html|title=Safety (MSDS) data for acetylsalicylic acid|url-status=dead|archive-url=https://web.archive.org/web/20110716144023/http://msds.chem.ox.ac.uk/AC/acetylsalicylic_acid.html|archive-date=2011-07-16|website=ox.ac.uk}}</ref>
|-
| [[Aspirin]] (acetylsalicylic acid)
| rat, oral
| 1,600&nbsp;mg/kg
| 1.6
| <ref>{{cite web|website=Millipore Sigma|publisher=Merck KGaA|url=https://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=US&language=en&productNumber=P0300000&brand=SIAL&PageToGoToURL=https%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fsearch%3Fterm%3DParacetamol%26interface%3DProduct%2520Name%26N%3D0%2B%26mode%3Dmode%2520matchpartialmax%26lang%3Den%26region%3DUS%26focus%3DproductN%3D0%2520220003048%2520219853286%2520219853121|title=Safety (MSDS) data for paracetamol|access-date=2020-01-06|archive-date=2021-03-02|archive-url=https://web.archive.org/web/20210302004449/https://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=US&language=en&productNumber=P0300000&brand=SIAL&PageToGoToURL=https%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fsearch%3Fterm%3DParacetamol%26interface%3DProduct%2520Name%26N%3D0%2B%26mode%3Dmode%2520matchpartialmax%26lang%3Den%26region%3DUS%26focus%3DproductN%3D0%2520220003048%2520219853286%2520219853121|url-status=live}}</ref>
|-
| [[Delta-9-tetrahydrocannabinol]] (THC)
| rat, oral
| 1,270&nbsp;mg/kg
| 1.27
| <ref>{{cite journal | vauthors = Rosenkrantz H, Heyman IA, Braude MC | title = Inhalation, parenteral and oral LD50 values of delta 9-tetrahydrocannabinol in Fischer rats | journal = Toxicology and Applied Pharmacology | volume = 28 | issue = 1 | pages = 18–27 | date = April 1974 | pmid = 4852457 | doi = 10.1016/0041-008X(74)90126-4 }}</ref>
|-
| [[Cannabidiol]] (CBD)
| rat, oral
| 980&nbsp;mg/kg
| 0.98
| <ref>{{cite web|url=http://www.chemblink.com/MSDS/MSDSFiles/13956-29-1_Clear%20Synth.pdf|title=MSDS of CBD|website=chemblink.com|access-date=2016-12-26|archive-url=https://web.archive.org/web/20161226150441/http://www.chemblink.com/MSDS/MSDSFiles/13956-29-1_Clear%20Synth.pdf|archive-date=2016-12-26|url-status=dead}}</ref>
|-
| [[Methanol toxicity|Methanol]] ({{chem2|CH3OH}})
| human, oral
| {{ntsh|5628}}810&nbsp;mg/kg
| 0.81
| <ref>{{cite web|url=http://www.antizol.com/mpoisono.htm|archive-url=https://web.archive.org/web/20111005043548/http://www.antizol.com/mpoisono.htm|url-status=dead|archive-date=2011-10-05|title=Methanol Poisoning Overview|website=antizol.com}}</ref>
|-
|[[TNT|Trinitrotoluene]] (TNT)
|rat, oral
|790&nbsp;mg/kg
|0.790
|
|-
| [[Arsenic poisoning|Arsenic]] (As)
| rat, oral
| 763&nbsp;mg/kg
| 0.763
| <ref>{{cite web|url=https://pubchem.ncbi.nlm.nih.gov/compound/5359596#section=Non-Human-Toxicity-Values|title=Arsenic|website=PubChem|access-date=2020-01-06|archive-date=2021-05-12|archive-url=https://web.archive.org/web/20210512235921/https://pubchem.ncbi.nlm.nih.gov/compound/5359596#section=Non-Human-Toxicity-Values|url-status=live}}</ref>
|-
| [[Ibuprofen]]
| rat, oral
| 636&nbsp;mg/kg
| 0.636
| <ref>{{cite web|url=https://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+3099|title=Ibuprofen – National Library of Medicine HSDB Database|website=toxnet.nlm.nih.gov|access-date=2016-12-26|archive-date=2018-08-04|archive-url=https://web.archive.org/web/20180804014036/https://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+3099|url-status=live}}</ref>
|-
| [[Formaldehyde]] ({{chem2|CH2O}})
| rat, oral
| 600–800&nbsp;mg/kg
| 0.6
| <ref>{{cite web|url=http://www.inchem.org/documents/sids/sids/FORMALDEHYDE.pdf|title=Formaldehyde SIDS Initial Assessment Report|website=inchem.org|access-date=2016-12-26|archive-url=https://web.archive.org/web/20180613195125/http://www.inchem.org/documents/sids/sids/formaldehyde.pdf|archive-date=2018-06-13|url-status=dead}}</ref>
|-
| [[Solanine]] (main alkaloid in the several plants in ''[[Solanaceae]]'' amongst them ''[[Solanum tuberosum]]'')
| rat, oral (2.8&nbsp;mg/kg human, oral)
| {{ntsh|590}}590&nbsp;mg/kg
| 0.590
|  <ref>{{cite web|url=https://chem.nlm.nih.gov/chemidplus/rn/20562-02-1|title=Solanine – National Library of Medicine HSDB Database|website=toxnet.nlm.nih.gov|access-date=2019-01-17|archive-date=2021-01-19|archive-url=https://web.archive.org/web/20210119060749/https://chem.nlm.nih.gov/chemidplus/rn/20562-02-1|url-status=live}}</ref>
|-
| [[ADBAC|Alkyl dimethyl benzalkonium chloride]] (ADBAC)
| rat, oral <br /> fish, immersion <br /> aquatic invertebrates, immersion
| 304.5&nbsp;mg/kg <br /> {0.28&nbsp;mg/L} <br /> {0.059&nbsp;mg/L}
| 0.3045 <br /> {0.00028} <br /> {0.000059}
|<ref name=epaRED>{{cite report
 |title=Reregistration Eligibility Decision for Alkyl Dimethyl Benzyl Ammonium Chloride (ADBAC) 
 |publisher=[[United States Environmental Protection Agency|U.S. Environmental Protection Agency]] Office of Prevention, Pesticides, and Toxic Substances 
 |editor=Frank T. Sanders 
 |date=August 2006 
 |url=http://www.epa.gov/oppsrrd1/REDs/adbac_red.pdf 
 |pages=114 
 |access-date=2009-03-31 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20091024165642/http://www.epa.gov/oppsrrd1/REDs/adbac_red.pdf 
 |archive-date=2009-10-24 
}}</ref>
|-
| [[Coumarin]] ([[benzopyrone]], from ''[[Cinnamomum aromaticum]]'' and other plants)
| rat, oral
| 293&nbsp;mg/kg
| 0.293
| <ref>[http://www.palomar.edu/ehs/Chemistry%20MSDS/COUMARIN.pdf Coumarin Material Safety Data Sheet (MSDS)] {{webarchive|url=https://web.archive.org/web/20041021205840/http://www.palomar.edu/ehs/Chemistry%20MSDS/COUMARIN.pdf |date=2004-10-21 }}</ref>
|-
| [[Psilocybin]] (from [[Psilocybin mushroom|psilocybin mushrooms]])
| mouse, oral
| 280&nbsp;mg/kg
| 0.280
| <ref>{{Cite book|url=https://books.google.com/books?id=WPWsZNvOqVAC&pg=PA211|title=Handbook of Mushroom Poisoning: Diagnosis and Treatment| vauthors = Rumack BH, Spoerke DJ |date=27 September 1994|publisher=CRC Press|via=Google Books|isbn=978-0-8493-0194-0}}</ref>
|-
| [[Hydrochloric acid]] (HCl)
| rat, oral
| 238–277&nbsp;mg/kg
| 0.238
| <ref>{{cite web |url=https://fscimage.fishersci.com/msds/11155.htm |title=Material Safety Data Sheet: Hydrochloric acid 32-38% solution |date=1 April 2008 |publisher=Fisher |access-date=24 December 2020 |archive-date=6 May 2021 |archive-url=https://web.archive.org/web/20210506124743/http://fscimage.fishersci.com/msds/11155.htm |url-status=live }}</ref>
|-
| [[Ketamine]]
| rat, intraperitoneal
| 229&nbsp;mg/kg
| 0.229
| <ref>{{cite web|url=https://ntp.niehs.nih.gov/ntp/htdocs/chem_background/exsumpdf/ketamine_508.pdf|title=Ketamine|website=nih.gov|access-date=2016-12-26|archive-date=2021-03-20|archive-url=https://web.archive.org/web/20210320091848/https://ntp.niehs.nih.gov/ntp/htdocs/chem_background/exsumpdf/ketamine_508.pdf|url-status=live}}</ref>
|-
| [[Caffeine]]
| rat, oral
| 192&nbsp;mg/kg
| 0.192
| <ref>{{cite journal | vauthors = Boyd EM | title = The acute oral toxicity of caffeine | journal = Toxicology and Applied Pharmacology | volume = 1 | issue = 3 | pages = 250–257 | date = May 1959 | pmid = 13659532 | doi = 10.1016/0041-008X(59)90109-7 | bibcode = 1959ToxAP...1..250B }}</ref>
|-
| [[Arsenic trisulfide]] ({{chem2|As2S3}})
| rat, oral
| 185–6,400&nbsp;mg/kg
| 0.185–6.4
| <ref>{{cite web|url=http://www.valero.com/V_MSDS/SpentMetalCatalyst901.pdf|archive-url=https://web.archive.org/web/20110928045935/http://www.valero.com/V_MSDS/SpentMetalCatalyst901.pdf|archive-date=2011-09-28|title=Material Safety Data Sheet – Spent Metal Catalyst}}</ref>
|-
| [[Sodium nitrite]] ({{chem2|NaNO2}})
| rat, oral
| 180&nbsp;mg/kg
| 0.18
| <ref>{{cite web|url=http://msds.chem.ox.ac.uk/MSDS/SO/sodium_nitrite.html|title=Safety (MSDS) data for sodium nitrite|website=ox.ac.uk}}{{dead link|date=January 2020}}</ref>
|-
| [[MDMA|Methylenedioxymethamphetamine]] (MDMA)
| rat, oral
| 160&nbsp;mg/kg
| 0.18
| <ref>{{cite journal | vauthors = Gable RS | title = Acute toxic effects of club drugs | journal = Journal of Psychoactive Drugs | volume = 36 | issue = 3 | pages = 303–313 | date = September 2004 | pmid = 15559678 | doi = 10.1080/02791072.2004.10400031 | s2cid = 30689421 }}</ref>
|-
| [[Uranyl acetate dihydrate]] ({{chem2|UO2(CH3COO)2}})
| mouse, oral
| 136&nbsp;mg/kg
| 0.136
| <ref name=Depluranium4>{{cite web|url=https://www.who.int/ionizing_radiation/pub_meet/en/Depluranium4.pdf|title=Chemical toxicity of uranium|website=who.int|access-date=2020-10-05|archive-date=2021-03-09|archive-url=https://web.archive.org/web/20210309174346/https://www.who.int/ionizing_radiation/pub_meet/en/Depluranium4.pdf|url-status=live}}</ref>
|-
| [[Dichlorodiphenyltrichloroethane]] (DDT)
| mouse, oral
| 135&nbsp;mg/kg
| 0.135
| <ref>{{cite book |doi=10.1007/978-3-0348-6809-9_3 |chapter=Dose-Mortality Relationships in Animals |title=DDT: The Insecticide Dichlorodiphenyltrichloroethane and Its Significance / Das Insektizid Dichlordiphenyltrichloräthan und Seine Bedeutung |year=1959 | vauthors = Hayes WJ, Simmons SW, Knipling EF |pages=18–40 |isbn=978-3-0348-6796-2 }}</ref>
|-
| [[Uranium]] (U)
| mice, oral 
| {{ntsh|114}}114&nbsp;mg/kg (estimated)
| 0.114
| <ref name=Depluranium4/>
|-
| [[Bisoprolol]]
| mouse, oral
| 100&nbsp;mg/kg
| 0.1
| <ref>{{cite web|url=http://www.drugbank.ca/drugs/DB00612|title=Bisoprolol|website=www.drugbank.ca|access-date=2012-06-13|archive-date=2020-06-17|archive-url=https://web.archive.org/web/20200617011336/https://www.drugbank.ca/drugs/DB00612|url-status=live}}</ref>
|-
| [[Cocaine]]
| mouse, oral
| 96&nbsp;mg/kg
| 0.096
| <ref>{{cite web|url=https://www.drugbank.ca/drugs/DB00907|title=Cocaine|website=www.drugbank.ca|access-date=2016-12-26|archive-url=https://web.archive.org/web/20161120184636/http://www.drugbank.ca/drugs/DB00907|archive-date=2016-11-20|url-status=dead}}</ref>
|-
| [[Cobalt(II) chloride]] ({{chem2|CoCl2}})
| rat, oral
| 80&nbsp;mg/kg
| 0.08
| <ref>{{cite web|url=http://msds.chem.ox.ac.uk/CO/cobalt_II_chloride.html|title=Safety (MSDS) data for cobalt (II) chloride|url-status=dead|archive-url=https://web.archive.org/web/20110407222057/http://msds.chem.ox.ac.uk/CO/cobalt_II_chloride.html|archive-date=2011-04-07|website=ox.ac.uk}}</ref>
|-
| [[Cadmium oxide]] (CdO)
| rat, oral
| 72&nbsp;mg/kg
| 0.072
| <ref>[http://assets.chemportals.merck.de/documents/sds/emd/deu/de/1020/102015.pdf Safety (MSDS) data for cadmium oxide]{{Dead link|date=December 2021 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
|-
| [[Thiopental sodium]] (used in [[lethal injection]])
| rat, oral
| 64&nbsp;mg/kg
| 0.064
| <ref>{{cite web|url=https://pubchem.ncbi.nlm.nih.gov/compound/thiopental_sodium#section=Non-Human-Toxicity-Values|title=Thiopental sodium|website=Pubchem|access-date=2017-01-06|archive-date=2021-01-26|archive-url=https://web.archive.org/web/20210126200735/https://pubchem.ncbi.nlm.nih.gov/compound/thiopental_sodium#section=Non-Human-Toxicity-Values|url-status=live}}</ref>
|-
| [[Demeton-S-methyl]]
| rat, oral
| 60&nbsp;mg/kg
| 0.060
| <ref>{{cite web|url=http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/demeton-s-methyl-ext.html|title=Demeton-s-methyl|date=September 1995|website=Extoxnet|access-date=2019-07-21|archive-date=2019-06-04|archive-url=https://web.archive.org/web/20190604152733/http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/demeton-s-methyl-ext.html|url-status=live}}</ref>
|-
| [[Methamphetamine]]
| rat, intraperitoneal
| 57&nbsp;mg/kg
| 0.057
| <ref>{{cite book |doi=10.1016/S0074-7742(09)88004-5 |chapter=Acute Methamphetamine Intoxication |title=New Concepts of Psychostimulant Induced Neurotoxicity |series=International Review of Neurobiology |year=2009 | vauthors = Kiyatkin EA, Sharma HS |volume=88 |pages=65–100 |pmid=19897075 |pmc=3145326 |isbn=978-0-12-374504-0 }}</ref>
|-
| [[Sodium fluoride]] (NaF)
| rat, oral
| 52&nbsp;mg/kg
| 0.052
| <ref>{{cite web|url=http://hazard.com/msds/mf/baker/baker/files/s3722.htm|title=Sodium fluoride|website=hazard.com|access-date=2011-07-31|archive-url=https://web.archive.org/web/20110928025825/http://hazard.com/msds/mf/baker/baker/files/s3722.htm|archive-date=2011-09-28|url-status=usurped}}</ref>
|-
| [[Nicotine]]
| mouse and rat, oral
human, smoking
| 50&nbsp;mg/kg
| 0.05
| <ref name=Mayer>{{cite journal | vauthors = Mayer B | title = How much nicotine kills a human? Tracing back the generally accepted lethal dose to dubious self-experiments in the nineteenth century | journal = Archives of Toxicology | volume = 88 | issue = 1 | pages = 5–7 | date = January 2014 | pmid = 24091634 | pmc = 3880486 | doi = 10.1007/s00204-013-1127-0 | bibcode = 2014ArTox..88....5M }}</ref>
|-
| [[Pentaborane]]
| human, oral
| 50&nbsp;mg/kg
| 0.05
| <ref>{{cite web|url=http://cameochemicals.noaa.gov/chris/PTB.pdf|title=Pentaborane chemical and safety data|website=noaa.gov|access-date=2011-09-30|archive-date=2013-05-23|archive-url=https://web.archive.org/web/20130523073131/http://cameochemicals.noaa.gov/chris/PTB.pdf|url-status=live}}</ref>
|-
| [[Capsaicin]]
| mouse, oral
| 47.2&nbsp;mg/kg
| 0.0472
| <ref>{{cite web |url=http://www.sciencelab.com/xMSDS-Capsaicin_Natural-9923296 |title=Capsaicin Material Safety Data Sheet |access-date=2007-07-13 |publisher=sciencelab.com |year=2007 |format=PDF |archive-url=https://web.archive.org/web/20070929083820/http://www.sciencelab.com/xMSDS-Capsaicin_Natural-9923296 |archive-date=2007-09-29 |url-status=dead }}</ref>
|-
| [[Vitamin D3]] (cholecalciferol)
| rat, oral
| 37&nbsp;mg/kg
| 0.037
| <ref>{{cite web|url=http://www.hmdb.ca/system/metabolites/msds/000/000/792/original/HMDB00876.pdf?1358463052|title=MSDS for cholecalciferol crystalline|website=hmdb.ca|access-date=2016-12-26|archive-url=https://web.archive.org/web/20161226145455/http://www.hmdb.ca/system/metabolites/msds/000/000/792/original/HMDB00876.pdf?1358463052|archive-date=2016-12-26|url-status=dead}}</ref>
|-
| [[Piperidine]] (from [[black pepper]])
| rat, oral
| 30&nbsp;mg/kg
| 0.030
| <ref>{{cite web |url=https://fscimage.fishersci.com/msds/18940.htm |title=Material Safety Data Sheet: Piperidine |date=29 October 2007 |publisher=Fisher |access-date=24 December 2020 |archive-date=4 March 2016 |archive-url=https://web.archive.org/web/20160304203049/https://fscimage.fishersci.com/msds/18940.htm |url-status=live }}</ref>
|-
| [[Heroin]] (diamorphine)
| mouse, intravenous
| 21.8&nbsp;mg/kg
| 0.0218
| <ref>{{cite web|url=http://www.inchem.org/documents/pims/pharm/pim261f.htm|title=Diamorphine (PIM 261F, French)|website=www.inchem.org|access-date=2016-12-26|archive-url=https://web.archive.org/web/20160502211029/http://www.inchem.org/documents/pims/pharm/pim261f.htm|archive-date=2016-05-02|url-status=dead}}</ref>
|-
| [[Lysergic acid diethylamide]] (LSD)
| rat, intravenous
| 16.5&nbsp;mg/kg
| 0.0165
| <ref>[http://www.erowid.org/chemicals/lsd/lsd_death.shtml Erowid LSD (Acid) Vault : Fatalities / Deaths] {{Webarchive|url=https://web.archive.org/web/20210630093733/https://www.erowid.org/chemicals/lsd/lsd_death.shtml |date=2021-06-30 }}. Erowid.org. Retrieved on 2013-07-17.</ref>
|-
| [[Arsenic trioxide]] ({{chem2|As2O3}})
| rat, oral
| 14&nbsp;mg/kg
| 0.014
| <ref>{{cite web|url=http://msds.chem.ox.ac.uk/AR/arsenic_III_oxide.html|title=Safety (MSDS) data for arsenic trioxide|url-status=dead|archive-url=https://web.archive.org/web/20100309164500/http://msds.chem.ox.ac.uk/AR/arsenic_III_oxide.html|archive-date=2010-03-09|website=ox.ac.uk}}</ref>
|-
| Metallic [[arsenic]] (As)
| rat, [[intraperitoneal]]
| 13&nbsp;mg/kg
| 0.013
| <ref>{{cite web|url=http://msds.chem.ox.ac.uk/AR/arsenic.html|title=Safety (MSDS) data for metallic arsenic|url-status=dead|archive-url=https://web.archive.org/web/20110114204809/http://msds.chem.ox.ac.uk/AR/arsenic.html|archive-date=2011-01-14|website=ox.ac.uk}}</ref>
|-
| [[Sodium cyanide]] (NaCN)
| rat, oral
| 6.4&nbsp;mg/kg
| 0.0064
| <ref>{{cite web|url=http://msds.chem.ox.ac.uk/SO/sodium_cyanide.html|title=Safety (MSDS) data for sodium cyanide|url-status=dead|archive-url=https://web.archive.org/web/20090113101513/http://msds.chem.ox.ac.uk/SO/sodium_cyanide.html|archive-date=2009-01-13|website=ox.ac.uk}}</ref>
|-
| [[Chlorotoxin]] (CTX, from [[scorpion]]s)
| mice
| 4.3&nbsp;mg/kg
| 0.0043
| <ref>{{cite web|url=https://www.researchgate.net/file.PostFileLoader.html?id=55280ed4cf57d70b0a8b45af&assetKey=AS%3A273754658148357%401442279604492|title=Chlorotoxin: A Helpful Natural Scorpion Peptide to Diagnose Glioma and Fight Tumor Invasion|access-date=2016-12-27|archive-date=2016-12-28|archive-url=https://web.archive.org/web/20161228195033/https://www.researchgate.net/file.PostFileLoader.html?id=55280ed4cf57d70b0a8b45af&assetKey=AS%3A273754658148357%401442279604492|url-status=live}}</ref>
|-
| [[Hydrogen cyanide]] (HCN)
| mouse, oral
| 3.7&nbsp;mg/kg
| 0.0037
| <ref>{{cite web|url=http://msds.orica.com/pdf/shess-en-cds-010-000032505901.pdf|title=Safety (MSDS) data for hydrogen cyanide|website=orica.com|access-date=2016-12-26|archive-url=https://web.archive.org/web/20161226150416/http://msds.orica.com/pdf/shess-en-cds-010-000032505901.pdf|archive-date=2016-12-26|url-status=dead}}</ref>
|-
| [[Carfentanil]]
| rat, intravenous
| 3.39&nbsp;mg/kg
| 0.00339
| <ref>{{cite web|url=https://www.who.int/medicines/access/controlled-substances/Critical_Review_Carfentanil.pdf|title=Critical Review Carfentanil|access-date=2019-01-31|archive-date=2020-11-12|archive-url=https://web.archive.org/web/20201112031048/https://www.who.int/medicines/access/controlled-substances/Critical_Review_Carfentanil.pdf|url-status=live}}</ref>
|-
| [[Nicotine]] (from various ''[[Solanaceae]] genera'')
| mice, oral
| 3.3&nbsp;mg/kg
| 0.0033
| <ref name=Mayer/>
|-
| [[White phosphorus]] (P)
| rat, oral
| 3.03&nbsp;mg/kg
| 0.00303
| <ref>{{cite web|url=http://www.atsdr.cdc.gov/toxprofiles/tp103-c2.pdf|title=Hexachloroethane|access-date=2014-01-03|archive-date=2006-06-30|archive-url=https://web.archive.org/web/20060630161253/http://www.atsdr.cdc.gov/toxprofiles/tp103-c2.pdf|url-status=live}}</ref>
|-
| [[Strychnine]] (from ''[[Strychnos nux-vomica]]'')
| human, oral
| 1–2&nbsp;mg/kg (estimated)
| 0.001–0.002
| <ref>[http://www.inchem.org/documents/pims/chemical/pim507.htm INCHEM: Chemical Safety Information from Intergovernmental Organizations: Strychnine] {{Webarchive|url=https://web.archive.org/web/20150103231725/http://www.inchem.org/documents/pims/chemical/pim507.htm |date=2015-01-03 }}.</ref>
|-
| [[Aconitine]] (from ''[[Aconitum napellus]]'' and related species)
| human, oral
| {{ntsh|.080}}1–2&nbsp;mg/kg
| 0.001–0.002
|  <ref>{{cite journal | vauthors = Gao X, Hu J, Zhang X, Zuo Y, Wang Y, Zhu S | title = Research progress of aconitine toxicity and forensic analysis of aconitine poisoning | journal = Forensic Sciences Research | volume = 5 | issue = 1 | pages = 25–31 | date = 2018-04-09 | pmid = 32490307 | pmc = 7241456 | doi = 10.1080/20961790.2018.1452346 }}</ref>
|-
| [[Mercury(II) chloride]] ({{chem2|HgCl2}})
| rat, oral
| 1&nbsp;mg/kg
| 0.001
| <ref>{{cite web|url=http://www.labchem.com/tools/msds/msds/LC16590.pdf|title=Mercuric Chloride Safety Data Sheet|page=6|website=LabChem|access-date=2020-01-06|archive-url=https://web.archive.org/web/20191126231854/http://www.labchem.com/tools/msds/msds/LC16590.pdf|archive-date=2019-11-26|url-status=dead}}</ref>
|-
| [[Cantharidin]] (from [[blister beetle]]s)
| human, oral
| 500&nbsp;μg/kg
| 0.0005
| <ref>{{Cite book| vauthors = Meister RT, Sine C |title=Crop Protection Handbook | volume = 99 |publisher=Meister Pub Co |year=2013 |isbn=978-1892829269 |location=Willoughby, Ohio |pages=664 }}</ref>
|-
| [[Aflatoxin|Aflatoxin B1]] (from ''[[Aspergillus flavus]]'' mold)
| rat, oral
| 480&nbsp;μg/kg
| 0.00048
| <ref>{{cite web|url=http://msds.chem.ox.ac.uk/AF/aflatoxin_B1|title=Safety (MSDS) data for aflatoxin B1|url-status=dead|archive-url=https://web.archive.org/web/20100811121705/http://msds.chem.ox.ac.uk/AF/aflatoxin_B1.html|archive-date=2010-08-11|website=ox.ac.uk}}</ref>
|-
| [[Plutonium]] (Pu)
| dog, intravenous
| 320&nbsp;μg/kg
| 0.00032
| <ref>{{cite journal|url=https://fas.org/sgp/othergov/doe/lanl/pubs/00818013.pdf|journal=[[Los Alamos Science]]|title=Plutonium and Health &mdash; How great is the risk?|vauthors=Voelz GL, Buican IG|issue=26|pages=74–89|date=2000|access-date=2016-12-26|archive-date=2021-01-18|archive-url=https://web.archive.org/web/20210118020351/https://fas.org/sgp/othergov/doe/lanl/pubs/00818013.pdf|url-status=live}}</ref>
|-
| [[Bufotoxin]] (from ''[[Bufo]]'' toads)
| cat, intravenous
| {{ntsh|.300}}300&nbsp;μg/kg
| 0.0003
| <ref>{{cite web|url=https://chem.nlm.nih.gov/chemidplus/rn/464-81-3|title=Bufotoxin|work=ChemIDplus|publisher=U.S. National Library of Medicine|access-date=2016-12-27|archive-date=2021-01-19|archive-url=https://web.archive.org/web/20210119064413/https://chem.nlm.nih.gov/chemidplus/rn/464-81-3|url-status=live}}</ref>
|-
| [[Brodifacoum]]
| rat, oral
| 270&nbsp;μg/kg
| 0.00027
| <ref>{{cite web|url=http://www.inchem.org/documents/pims/chemical/pim077.htm |title=Brodifacoum (PDS) |publisher=Inchem.org |access-date=2017-12-05 |url-status=live |archive-url=https://web.archive.org/web/20131213084637/http://www.inchem.org/documents/pds/pds/pest57_e.htm |archive-date=2013-12-13 }}</ref>
|-
| [[Caesium-137]] ({{chem|137|Cs}})
| mouse, parenteral
| {{ntsh|.215}}21.5&nbsp;μCi/g 
| 0.000245
| <ref>{{cite book | vauthors = Moskalev YI |chapter=Biological Effects of Cesium-137| veditors = Lebedinskiĭ AV, Moskalev YI |title=Distribution, Biological Effects, and Migration of Radioactive Isotopes|series=Translation Series|publisher=United States Atomic Energy Commission|id=AEC-tr-7512|page=220|publication-date=April 1974|date=1961|chapter-url=https://books.google.com/books?id=K4wPAQAAMAAJ&pg=PA220|url=https://books.google.com/books?id=K4wPAQAAMAAJ}} [(21.5&nbsp;μCi/g) × (1000&nbsp;g/kg) × (0.0114&nbsp;μg/μCi) = 245&nbsp;μg/kg]</ref>
|-
|[[Sodium fluoroacetate]] ({{chem2|CH2FCOONa}})
|rat, oral
|220&nbsp;μg/kg
|0.00022
|<ref>{{Cite book| vauthors = Meister R, Since C |title=Crop Protection Handbook 2013 |publisher=Meister Pub Co|year=2013|isbn=9781892829269|location=Willoughby, Ohio|pages=664}}</ref>
|-
|[[Chlorine trifluoride]] (ClF<sub>3</sub>)
|mouse, absorption through skin
|178&nbsp;μg/kg
|0.000178
|<ref>{{Cite web |date=2018-11-02 |title=CDC - Immediately Dangerous to Life or Health Concentrations (IDLH): Chlorine trifluoride - NIOSH Publications and Products |url=https://www.cdc.gov/niosh/idlh/7790912.html |access-date=2022-07-13 |website=www.cdc.gov |language=en-us |archive-date=2022-07-11 |archive-url=https://web.archive.org/web/20220711073705/https://www.cdc.gov/niosh/idlh/7790912.html |url-status=live }}</ref>
|-
| [[Sarin]]
| mouse, subcutaneous injection
| {{ntsh|.172}}172&nbsp;μg/kg
| 0.000172
| <ref>{{cite journal | vauthors = Inns RH, Tuckwell NJ, Bright JE, Marrs TC | title = Histochemical demonstration of calcium accumulation in muscle fibres after experimental organophosphate poisoning | journal = Human & Experimental Toxicology | volume = 9 | issue = 4 | pages = 245–250 | date = July 1990 | pmid = 2390321 | doi = 10.1177/096032719000900407 | bibcode = 1990HETox...9..245I | s2cid = 20713579 }}</ref>
|-
| [[Robustoxin]] (from [[Sydney funnel-web spider]])
| mice
| {{ntsh|.150}}150&nbsp;μg/kg
| 0.000150
| <ref>{{cite journal | vauthors = Sheumack DD, Baldo BA, Carroll PR, Hampson F, Howden ME, Skorulis A | title = A comparative study of properties and toxic constituents of funnel web spider (Atrax) venoms | journal = Comparative Biochemistry and Physiology. C, Comparative Pharmacology and Toxicology | volume = 78 | issue = 1 | pages = 55–68 | year = 1984 | pmid = 6146485 | doi = 10.1016/0742-8413(84)90048-3 }}</ref>
|-
| [[VX (nerve agent)|VX]]
| human, oral, inhalation, absorption through skin/eyes
| {{ntsh|.14}}140&nbsp;μg/kg (estimated)
| 0.00014
| <ref>{{cite journal | vauthors = Munro N | title = Toxicity of the organophosphate chemical warfare agents GA, GB, and VX: implications for public protection | journal = Environmental Health Perspectives | volume = 102 | issue = 1 | pages = 18–38 | date = January 1994 | pmid = 9719666 | pmc = 1567233 | doi = 10.1289/ehp.9410218 | bibcode = 1994EnvHP.102...18M }}</ref>
|-
| Venom of the [[Brazilian wandering spider]]
| rat, subcutaneous
| {{ntsh|.134}}134&nbsp;μg/kg
| 0.000134
| <ref>''Venomous Animals and their Venoms'', vol. III, ed. Wolfgang Bücherl and Eleanor Buckley</ref>
|-
| [[Amatoxin]] (from ''[[Amanita phalloides]]'' mushrooms)
| human, oral
| 100&nbsp;μg/kg
| 0.0001
| <ref>{{cite journal | vauthors = Hallen HE, Luo H, Scott-Craig JS, Walton JD | title = Gene family encoding the major toxins of lethal Amanita mushrooms | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 104 | issue = 48 | pages = 19097–19101 | date = November 2007 | pmid = 18025465 | pmc = 2141914 | doi = 10.1073/pnas.0707340104 | doi-access = free }}</ref><ref>{{cite book | vauthors = Madore F, Bouchard J | chapter = Plasmapheresis in Acute Intoxication and Poisoning |date=2019 | title = Critical Care Nephrology |pages=595–600.e3 |publisher=Elsevier |language=en |doi=10.1016/b978-0-323-44942-7.00100-x |isbn=978-0-323-44942-7 }}</ref>
|-
|[[Dimethylmercury]] ({{chem2|Hg(CH3)2}})
|human, transdermal
|{{ntsh|.080}}50&nbsp;μg/kg
|0.000050
|<ref>{{cite journal | vauthors = Blayney MB | title = The need for empirically derived permeation data for personal protective equipment: the death of Dr. Karen E. Wetterhahn | journal = Applied Occupational and Environmental Hygiene | volume = 16 | issue = 2 | pages = 233–236 | date = February 2001 | pmid = 11217716 | doi = 10.1080/104732201460389 }}</ref>
|-
|[[TBPO]] (t-Butyl-bicyclophosphate)
|mouse, intravenous
|36&nbsp;μg/kg
|0.000036
|<ref name="pmid452023">{{cite journal | vauthors = Milbrath DS, Engel JL, Verkade JG, Casida JE | title = Structure--toxicity relationships of 1-substituted-4-alkyl-2,6,7-trioxabicyclo[2.2.2.]octanes | journal = Toxicology and Applied Pharmacology | volume = 47 | issue = 2 | pages = 287–293 | date = February 1979 | pmid = 452023 | doi = 10.1016/0041-008x(79)90323-5 | bibcode = 1979ToxAP..47..287M }}</ref>
|-
| [[Fentanyl]]
| monkey
| 30&nbsp;μg/kg
| 0.00003
| <ref>{{cite web|url=https://www.drugbank.ca/drugs/DB00813|title=Fentanyl|website=www.drugbank.ca|access-date=2017-09-29|archive-url=https://web.archive.org/web/20170711073330/https://www.drugbank.ca/drugs/DB00813|archive-date=2017-07-11|url-status=dead}}</ref>
|-
| Venom of the [[inland taipan]] 
| rat, subcutaneous
| {{ntsh|.025}}25&nbsp;μg/kg
| 0.000025
| <ref>[http://www.seanthomas.net/oldsite/ld50tot.html LD50 for various snakes] {{webarchive|url=https://web.archive.org/web/20120201062634/http://www.seanthomas.net/oldsite/ld50tot.html |date=2012-02-01 }}. Seanthomas.net. Retrieved on 2013-07-17.</ref>
|-
| [[Ricin]] (from [[castor oil plant]])
| rat, intraperitoneal <br /> rat, oral
| {{ntsh|.022}}22&nbsp;μg/kg <br /> 20–30&nbsp;mg/kg
| 0.000022 <br /> 0.02
| <ref>{{cite journal |title=Ricin (from ''Ricinus communis'') as undesirable substances in animal feed - Scientific Opinion of the Panel on Contaminants in the Food Chain |journal=EFSA Journal |year=2008 |volume=6 |issue=9 |page=726 |doi=10.2903/j.efsa.2008.726 |citeseerx=10.1.1.333.8413 }}</ref>
|-
| [[2,3,7,8-Tetrachlorodibenzodioxin]] (TCDD, in [[Agent Orange]])
| rat, oral
| {{ntsh|.02}}20&nbsp;μg/kg
| 0.00002
|
|-
| [[Tetrodotoxin]] from the [[blue-ringed octopus]]
| intravenous
| {{ntsh|.0082}}8.2&nbsp;μg/kg
| 0.0000082
| <ref>{{cite journal | vauthors = Knutsen HK, Alexander J, Barregård L, Bignami M, Brüschweiler B, Ceccatelli S, Cottrill B, Dinovi M, Edler L, Grasl-Kraupp B, Hogstrand C, Hoogenboom LR, Nebbia CS, Oswald IP, Rose M, Roudot AC, Schwerdtle T, Vleminckx C, Vollmer G, Wallace H, Arnich N, Benford D, Botana L, Viviani B, Arcella D, Binaglia M, Horvath Z, Steinkellner H, van Manen M, Petersen A | title = Risks for public health related to the presence of tetrodotoxin (TTX) and TTX analogues in marine bivalves and gastropods | journal = EFSA Journal. European Food Safety Authority | volume = 15 | issue = 4 | pages = e04752 | date = April 2017 | pmid = 32625458 | pmc = 7010203 | doi = 10.2903/j.efsa.2017.4752 | s2cid = 54043321 | doi-access = free }}</ref>
|-
| CrTX-A (from ''[[Carybdea rastonii]]'' [[box jellyfish]] [[venom]])
| crayfish, intraperitoneal
| {{ntsh|.005}}5&nbsp;μg/kg
| 0.000005
| <ref>{{cite journal | vauthors = Nagai H |title=Recent Progress in Jellyfish Toxin Study |journal=Journal of Health Science |date=2003 |volume=49 |issue=5 |pages=337–340 |doi=10.1248/jhs.49.337 |doi-access=free }}</ref>
|-
| [[Latrotoxin]] (from [[Latrodectus|widow spider]] [[venom]])
| mice
| {{ntsh|.0043}}4.3&nbsp;μg/kg
| 0.0000043
| <ref>{{Cite web |url=http://biology.unm.edu/toolson/biotox/presentations_2013/ALPHA-LATROTOXIN%20POWERPOINT.pptx |title=Black Widow Venom (α-Latrotoxin) | vauthors = Henderson N, Wright K, Morgan D, Tantum P |format=pptx |access-date=2016-12-26 |archive-url=https://web.archive.org/web/20161226221309/http://biology.unm.edu/toolson/biotox/presentations_2013/ALPHA-LATROTOXIN%20POWERPOINT.pptx |archive-date=2016-12-26 |url-status=dead }}</ref>{{self-published inline|date=December 2020}}
|-
|[[Epibatidine]] (from ''[[Epipedobates anthonyi]]'' poison dart frog)
|mouse, intravenous
|1.46-13.98&nbsp;μg/kg
|0.00000146
|<ref>{{cite journal | vauthors = Sihver W, Långström B, Nordberg A | title = Ligands for in vivo imaging of nicotinic receptor subtypes in Alzheimer brain | journal = Acta Neurologica Scandinavica. Supplementum | volume = 176 | issue = s176 | pages = 27–33 | date = 2000 | pmid = 11261802 | doi = 10.1034/j.1600-0404.2000.00304.x | s2cid = 23541883 | doi-access = free }}</ref>
|-
| [[Batrachotoxin]] (from [[poison dart frog]])
| human, sub-cutaneous injection
| {{ntsh|.002}}2–7&nbsp;μg/kg (estimated)
| 0.000002
| <ref name=":0">{{cite journal | vauthors = Patocka J, Streda L |year=2002 |title=Brief review of natural nonprotein neurotoxins |journal=ASA Newsletter |volume=2 |issue=2 |pages=16–24 }}</ref>
|-
|[[Abrin]] (from [[rosary pea]])
|mice, intravenously<br>human, inhalation<br>human, oral 
|0.7&nbsp;μg/kg<br>3.3&nbsp;μg/kg<br>10–1000&nbsp;μg/kg 
|0.0000007<br>0.0000033<br>0.00001–0.001
|{{Citation needed|date=June 2024}}
|-
|[[Saxitoxin]] (from certain marine [[dinoflagellate]]s)
|human, intravenously<br>human, oral
|0.6&nbsp;μg/kg<br>5.7&nbsp;μg/kg
|0.0000006<br>0.0000057
|<ref name=":0" />
|-
| Pacific [[ciguatoxin]]-1 (from [[Ciguatera|ciguateric fish]])
| mice, intraperitoneal
| 250&nbsp;ng{{ntsh|.00025}}/kg
| 0.00000025
|<ref>{{cite journal | vauthors = Caillaud A, de la Iglesia P, Darius HT, Pauillac S, Aligizaki K, Fraga S, Chinain M, Diogène J | title = Update on methodologies available for ciguatoxin determination: perspectives to confront the onset of ciguatera fish poisoning in Europe | journal = Marine Drugs | volume = 8 | issue = 6 | pages = 1838–1907 | date = June 2010 | pmid = 20631873 | pmc = 2901828 | doi = 10.3390/md8061838 | doi-access = free }}</ref>
|-
|[[Palytoxin]] (from ''[[Palythoa]]'' coral)
|mouse, intravenous<br>{{Fix|text=What do the 2 different figures represent?}}
|45&nbsp;ng/kg<br>2.3–31.5&nbsp;μg/kg
|0.000000045<br>0.0000023
|<ref>{{cite journal | vauthors = Ramos V, Vasconcelos V | title = Palytoxin and analogs: biological and ecological effects | journal = Marine Drugs | volume = 8 | issue = 7 | pages = 2021–2037 | date = June 2010 | pmid = 20714422 | pmc = 2920541 | doi = 10.3390/md8072021 | doi-access = free }}</ref>
|-
| [[Maitotoxin]] (from [[Ciguatera|ciguateric fish]])
| mouse, [[intraperitoneal]]
| 50&nbsp;ng{{ntsh|.00005}}/kg
| 0.00000005
|<ref>{{cite web | url=https://pubchem.ncbi.nlm.nih.gov/compound/maitotoxin | publisher=[[National Center for Biotechnology Information]] | title=PubChem Compound Summary for CID 71460273, Maitotoxin | work=[[PubChem]] | access-date=2020-12-25 | archive-date=2020-11-01 | archive-url=https://web.archive.org/web/20201101135722/https://pubchem.ncbi.nlm.nih.gov/compound/Maitotoxin | url-status=live }}</ref>
|-
| [[Polonium-210]] ({{chem|210|Po}})
| human<!-- double check reference -->, inhalation
| {{ntsh|.00001}}10&nbsp;ng/kg (estimated)
| 0.00000001
| <ref>[http://agrippina.deakin.edu.au/occ-hyg/sbc312/sbc312-07/SBC312-Topic2-07.htm Topic 2 Toxic Chemicals and Toxic Effects] {{webarchive|url=https://web.archive.org/web/20070929131217/http://agrippina.deakin.edu.au/occ-hyg/sbc312/sbc312-07/SBC312-Topic2-07.htm |date=2007-09-29 }}</ref>
|-
| [[Diphtheria toxin]] (from ''[[Corynebacterium]]'')
| mice
| {{ntsh|.00001}}10&nbsp;ng/kg
| 0.00000001
| <ref name="biology.unm.edu">{{Cite web |url=http://biology.unm.edu/toolson/biotox/representative_LD50_values.pdf |title=Representative LD<sub>50</sub> Values | vauthors = Toolson E |access-date=2016-12-26 |archive-url=https://web.archive.org/web/20150412045434/http://biology.unm.edu/toolson/biotox/representative_LD50_values.pdf |archive-date=2015-04-12 |url-status=dead }}</ref>
|-
| [[Shiga toxin]] (from ''[[Shigella]]'' bacteria)
| mice
| {{ntsh|.000002}}2&nbsp;ng/kg
| 0.000000002
| <ref name="biology.unm.edu"/>
|-
| [[Tetanospasmin]] (from ''[[Clostridium tetani]]'')
| mice
| {{ntsh|.000002}}2&nbsp;ng/kg
| 0.000000002
| <ref name="biology.unm.edu"/>
|-
| [[Botulinum toxin]] (from ''[[Clostridium botulinum]]'')
| human, oral, injection, inhalation
| {{ntsh|.000001}}1&nbsp;ng/kg (estimated)
| 0.000000001
| <ref>{{cite book | vauthors = Fleming DO, Hunt DL |title=Biological Safety: principles and practices |publisher=ASM Press |location=Washington, DC |year=2000 |page=[https://archive.org/details/biologicalsafety0000unse_3rdedition/page/267 267] |isbn=978-1-55581-180-8 |url=https://archive.org/details/biologicalsafety0000unse_3rdedition/page/267 }}</ref>
|-
| [[Ionizing radiation]]
| human, irradiation
| 3–5&nbsp;[[Gray (unit)|Gy]] (Gray)
| —
|<ref>{{cite journal | vauthors = Ryan JL | title = Ionizing radiation: the good, the bad, and the ugly | journal = The Journal of Investigative Dermatology | volume = 132 | issue = 3 Pt 2 | pages = 985–993 | date = March 2012 | pmid = 22217743 | pmc = 3779131 | doi = 10.1038/jid.2011.411 }}</ref><ref>{{cite web |date=2013 |title=Lethal dose |url=https://www.euronuclear.org/info/encyclopedia/l/lethal-dose.htm |url-status=dead |archive-url=https://web.archive.org/web/20180804014252/https://www.euronuclear.org/info/encyclopedia/l/lethal-dose.htm |archive-date=2018-08-04 |access-date=2018-09-15 |website=www.euronuclear.org |vauthors=Winfried K}}</ref><ref>{{Cite web |date=2022-12-13 |title=Radiation Exposure - Dose and Dose Rate (the Gray & Sievert) |url=https://ionactive.co.uk/resource-hub/guidance/radiation-exposure-dose-and-dose-rate-the-gray-sievert |access-date=2024-07-27 |website=Ionactive}}</ref>
|}

== Poison scale ==
[[File:Poison-Scale-long.jpg|thumb|700px| Negative values of the [[decimal logarithm]] of the median lethal dose LD<sub>50</sub> ({{math|&minus;log<sub>10</sub>(LD<sub>50</sub>)}}) on a linearized toxicity scale encompassing 11 orders of magnitude. Water occupies the lowest toxicity position (1) while the toxicity scale is dominated by the [[botulinum toxin]] (12).<ref>{{cite journal | vauthors= Strey, Karsten | title = Die Gifte-Skala | journal = Chemie in unserer Zeit | volume=53 | issue = 6 | pages = 386–399 | date = December 2019 | doi = 10.1002/ciuz.201900828 | s2cid = 199067092 }}</ref>]]

The LD<sub>50</sub> values have a very wide range. The [[botulinum toxin]] as the most toxic substance known has an LD<sub>50</sub> value of 1&nbsp;ng/kg, while the most non-toxic substance [[water]] has an LD<sub>50</sub> value of more than 90&nbsp;g/kg; a difference of about 1 in 100 billion, or 11 orders of magnitude. As with all measured values that differ by many orders of magnitude, a logarithmic view is advisable. Well-known examples are the indication of the earthquake strength using the [[Richter scale]], the [[pH value]], as a measure for the acidic or basic character of an aqueous solution or of [[Sound pressure#Sound pressure level|loudness]] in [[decibel]]s.
In this case, the negative decimal logarithm of the LD<sub>50</sub> values, which is standardized in kg per kg body weight, is considered {{math|&minus;log<sub>10</sub>(LD<sub>50</sub>)}}.

The dimensionless value found can be entered in a toxin scale. Water as the baseline substance is nearly 1 in the negative logarithmic toxin scale.

== Procedures ==
A number of procedures have been defined to derive the LD<sub>50</sub>. The earliest was the 1927 "conventional" procedure by Trevan, which requires 40 or more animals. The [[fixed-dose procedure]], proposed in 1984, estimates a level of toxicity by feeding at defined doses and looking for signs of toxicity (without requiring death).<ref>{{cite journal | vauthors = van den Heuvel MJ, Clark DG, Fielder RJ, Koundakjian PP, Oliver GJ, Pelling D, Tomlinson NJ, Walker AP | title = The international validation of a fixed-dose procedure as an alternative to the classical LD50 test | journal = Food and Chemical Toxicology | volume = 28 | issue = 7 | pages = 469–482 | date = July 1990 | pmid = 2210519 | doi = 10.1016/0278-6915(90)90117-6 }}</ref> The [[up-and-down procedure]], proposed in 1985, yields an LD<sub>50</sub> value while dosing only one animal at a time.<ref>{{cite journal | vauthors = Lipnick RL, Cotruvo JA, Hill RN, Bruce RD, Stitzel KA, Walker AP, Chu I, Goddard M, Segal L, Springer JA | title = Comparison of the up-and-down, conventional LD<sub>50</sub>, and fixed-dose acute toxicity procedures | journal = Food and Chemical Toxicology | volume = 33 | issue = 3 | pages = 223–231 | date = March 1995 | pmid = 7896233 | doi = 10.1016/0278-6915(94)00136-c }}</ref><ref>{{cite journal | vauthors = Lichtman AH | title = The up-and-down method substantially reduces the number of animals required to determine antinociceptive ED50 values | journal = Journal of Pharmacological and Toxicological Methods | volume = 40 | issue = 2 | pages = 81–85 | date = August 1998 | pmid = 10100496 | doi = 10.1016/s1056-8719(98)00041-0 }}</ref>

== See also ==
* [[Animal testing]]
* [[Reed-Muench method]]
* [[The dose makes the poison]] – the toxicology adage that high quantities of any substance is lethal

=== Other measures of toxicity ===
{{div col}}
* [[IDLH]]
* [[Certain safety factor]]
* [[Therapeutic index]]
* [[Protective index]]
* [[Median toxic dose]] (TD50)
* [[Lowest published lethal dose]] (LDLo)
* [[EC50|EC<sub>50</sub>]] (half maximal effective concentration)
* [[IC50|IC<sub>50</sub>]] (half maximal inhibitory concentration)
* [[Draize test]]
* [[Indicative limit value]]
* [[No-observed-adverse-effect level]] (NOAEL)
* [[Lowest-observed-adverse-effect level]] (LOAEL)
{{div col end}}

=== Related measures ===
* [[TCID50|TCID<sub>50</sub>]] Tissue Culture Infective Dosage
* [[Plaque forming units]] (pfu)

== References ==
{{reflist|30em}}

== Further reading ==
{{refbegin}}
* {{cite journal | vauthors = Lipnick RL, Cotruvo JA, Hill RN, Bruce RD, Stitzel KA, Walker AP, Chu I, Goddard M, Segal L, Springer JA | title = Comparison of the up-and-down, conventional LD50, and fixed-dose acute toxicity procedures | journal = Food and Chemical Toxicology | volume = 33 | issue = 3 | pages = 223–231 | date = March 1995 | pmid = 7896233 | doi = 10.1016/0278-6915(94)00136-C }}
{{refend}}

== External links ==
* [http://www.ccohs.ca/oshanswers/chemicals/ld50.html Canadian Centre for Occupational Health and Safety] {{Webarchive|url=https://web.archive.org/web/20150626013647/http://www.ccohs.ca/oshanswers/chemicals/ld50.html |date=2015-06-26 }}

{{Pharmacology}}
{{Toxicology}}

{{DEFAULTSORT:Median Lethal Dose}}
[[Category:Causes of death]]
[[Category:Animal testing]]
[[Category:Concentration indicators]]
[[Category:Mathematics in medicine]]
[[Category:Toxicology]]