Median lethal dose

"LD50" redirects here. For other uses, see LD50 (disambiguation).

In toxicology, the median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a given substance.[1] The value of LD50 for a substance is the dose required to kill half the members of a tested population after a specified test duration. LD50 figures are frequently used as a general indicator of a substance's acute toxicity. A lower LD50 is indicative of higher toxicity.

The term LD50 is generally attributed to John William Trevan.[2] The test was created by J. W. Trevan in 1927.[3] 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. LD50 is usually determined by tests on animals such as laboratory mice. In 2011, the U.S. Food and Drug Administration approved alternative methods to LD50 for testing the cosmetic drug Botox without animal tests.[4][5]

  1. ^ "Absolute lethal dose (LD100)". IUPAC Gold Book. International Union of Pure and Applied Chemistry. Archived from the original on 2019-07-01. Retrieved 2019-07-01.
  2. ^ "John William Trevan, 1887-1956". Biographical Memoirs of Fellows of the Royal Society. 3: 273–288. 1957. doi:10.1098/rsbm.1957.0019. ISSN 0080-4606. Archived from the original on 2020-03-28. Retrieved 2024-03-31.
  3. ^ "What is a LD50 and LC50?". OSH Answers Fact Sheets. Canadian Centre for Occupational Health and Safety. 5 October 2021. Archived from the original on 26 June 2015. Retrieved 15 July 2006.
  4. ^ "Allergan Receives FDA Approval for First-of-Its-Kind, Fully in vitro, Cell-Based Assay for BOTOX and BOTOX Cosmetic (onabotulinumtoxinA)". Allergan Web site. 24 June 2011. Archived from the original on 26 June 2011. Retrieved 2012-08-15.
  5. ^ Gaul GM (12 April 2008). "In U.S., Few Alternatives To Testing On Animals". Washington Post. Archived from the original on 2012-11-12. Retrieved 2011-06-26.