The allethrins are a pair of related synthetic compounds used in insecticides. They are synthetic pyrethroids, a synthetic form of a chemical found naturally in the chrysanthemum flower. They were first synthesized in the United States by Milton S. Schechter in 1949. Allethrin was the first pyrethroid.

The compounds have low toxicity for humans and birds, and are used in many household insecticides such as RAID as well as mosquito coils. They are, however, highly toxic to fish and bees. Insects subject to its exposure become paralyzed (nervous system effect) before dying. They are also highly toxic to cats because[1] they either do not produce, or produce less of certain isoforms of glucuronosyltransferase, which serve in hepatic detoxifying metabolism pathways.[2]

They are also used as an ultra-low volume spray for outdoor mosquito control.


Each allethrin consists of the eight possible stereoisomers. A partly enantiopure variant of allethrin I, consisting of only two stereoisomers, is called bioallethrin.


  • Oregon State University (1996). Allethrin. Retrieved October 26, 2005.
  • Illinois Department of Public Health Pyrethroid Insecticides Fact Sheet. Retrieved October 26, 2005.
  • d-Allethrin. Retrieved October 26, 2005.
  • Jim E. Riviere & Mark G. Papich Eds.: Veterinary Pharmacology and Therapeutics. Iowa State University Press, 2009. ISBN 13: 9780813820613, ISBN 10: 0813820618. (p. 1194)

External links

  • Pyrethrins and Pyrethroids Fact Sheet - National Pesticide Information Center
  • Allethrin Pesticide Information Profile - Extension Toxicology Network