Lethal dose 50

Article By:

White, Colin Department of Epidemiology and Public Health, Yale University, New Haven, Connecticut.

Last reviewed:September 2021

DOI:https://doi.org/10.1036/1097-8542.378800

Show previous versions

• Lethal dose 50, published August 2020:Download PDF Get Adobe Acrobat Reader
• Lethal dose 50, published June 2014:Download PDF Get Adobe Acrobat Reader

An estimation of the acute toxicity of an administered material that is lethal for half of the animals in an experimental group. The lethal dose 50 (median lethal dose), which is often written as LD₅₀, is a measure of acute toxicity (short-term poisoning potential) resulting from administration of an amount (dose) of a substance that is lethal for half (50%) of the animals in a test group (see illustration). Specifically, the LD₅₀ is a type of effective dose 50 (median effective dose, which characterizes the potency of a drug by the amount required to produce a response in 50% of the subjects to whom the drug is given). Thus, the LD₅₀ is used when the response being investigated is the death of the experimental animal. In other words, the median lethal dose (that is, LD₅₀) is the dose that is fatal to 50% of the test animals. See also: Effective dose 50; Pharmacology; Pharmacy; Toxicology

The content above is only an excerpt.