Pyrethrins are natural insecticides derived from chrysanthemum flowers containing a mixture of six components: pyrethrin I, cinerin I, jasmolin I, pyrethrin II, cinerin II, and jasmolin II. Pyrethrin I is one of the two pyrethrins, natural organic compounds with potent insecticidal activity. It is an ester of ( )-trans-chrysanthemic acid with (S)-(Z)-pyrethrolone. Pyrethrins induce a toxic effect in insects when they penetrate the cuticle and reach the nervous system. Pyrethrins bind to sodium channels that occur along the length of nerve cells. Sodium channels are responsible for nerve signal transmission along the length of the nerve cell by permitting the flux of sodium ions. When pyrethrins bind to sodium channels, normal function of the channels is obstructed thereby resulting in hyperexcitation of the nerve cell and, consequently, a loss of function of the nerve cell. The shutdown of the insect nervous system and death are most often the consequences of insect exposure to pyrethrins.