cat unit

cat unit2016-11-05T17:40:35+00:00

cat unit

cat unit image from New Medical Terms

cat unit


A biological assay corresponding to the minimum amount of a substance (expressed in g/kg) which is lethal to cats when injected IV. In practice, the LD50 for acute toxicity would be measured in rodents.

From what I can gather, cat units were last used by Western pharmacologists and physiologists in the mid-1940s. PETA–People for the Ethical Treatment of Animals has effectively squelched using cats in biological assays. A text (see reference) on Chinese traditional medicine refers to it as recently as 1998, which is hardly surprising, given that in China, cats are as likely to be à la carte as they are à la couch. 

References Annual Review of Physiology March 1943; Vol. 5: 479-539

DOI: 10.1146/

Amdur, J Doull, CD Klaassen, Eds, Toxicology, 4th ed, McGraw-Hill, New York, 1991

You-Ping Zhu, Chinese Materia Medica: Chemistry, Pharmacology and Applications CRC Press, 1998


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