LD50

In toxicology, the LD50 or colloquially semilethal dose of a particular substance is a measure of how much constitutes a lethal dose. The test was created by J.W. Trevan in 1927. In animal testing studies, the dose administered that kills half the test population is referred to as the LD50, for "Lethal Dose, 50%".

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Two species are normally required to be involved in the testing. A feeding syringe is forced down the animals? throats, injecting into the stomach a chemical ingredient of the product, or the product itself, often household cleaners or gardening products like weedkillers. The forced feeding increases in amount until half the animals are dead, after experiencing vomiting and convulsions. Technicians note quantity required to kill 50% of the animals, and then the survivors are killed. No harmful effects are measured, just the lethal dose.

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Animal-rights and animal-welfare groups have campaigned against the LD50 test, citing it as cruel and unnecessary, and in the case of some substances, causing the animals to die slow, painful deaths. As a result, several countries, including the UK, have taken steps to ban it, and the Organisation for Economic Co-operation and Development (OECD) abolished the requirement for it in 2001 (see Test Guideline 401, Trends in Pharmacological Sciences Vol 22, February 22, 2001).

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Toxicology: Toxicology (from the Greek words toxicon and logos) is the study of the adverse effects of chemicals on living organisms. It is the study of symptoms, mechanisms, treatments and detection of biological poisoning, especially the poisoning of people. The chief criterion regarding the toxicity of a ch...

Animal testing: Animal testing is the use of non-human animals in experiments. These may be for the purpose of testing certain substances to determine their effect on humans, or to test medical or psychological hypotheses. The topic is mired in controversy with supporters and opponents arguing over both ethical con...

%: "?", "?" is a vowel and a letter used in the Danish, Faroese and Norwegian alphabets....