The
pyrethrins are a class of
organic compounds normally derived from
Chrysanthemum cinerariifolium that have potent
insecticidal activity by targeting the nervous systems of
insects. Pyrethrin is synthetically made by industrial methods, but it also naturally occurs in the Chrysanthemum flowers, and thus is often considered an
organic insecticide, or at least when is not combined with
piperonyl butoxide or other synthetic
adjuvants. Their insecticidal and insect repellent properties have been known and utilized for thousands of years.