Chrysanthemic acid is an organic compound that is related to a variety of natural and synthetic insecticides.

One of the four stereoisomers, (1R,3R)- or (+)-trans-chrysanthemic acid (pictured), is the acid part of the ester pyrethrin I, which occurs naturally in the seed cases of Chrysanthemum cinerariaefolium.

[2] Chrysanthemic acid is derived from its pyrophosphate ester, which in turn is produced naturally from two molecules of dimethylallyl diphosphate.

Chrysanthemic acid is produced industrially in a cyclopropanation reaction of a diene as a mixture of cis- and trans isomers, followed by hydrolysis of the ester:[4]

Many pyrethroids are accessible by re-esterification of chrysanthemic acid ethyl ester - a perfume ingredient.