noun , Chemistry. Also called pyrethrin I. a viscous, water-insoluble liquid, C 2 1 H 2 8 O 3 , extracted from pyrethrum flowers, used as an insecticide. Also called pyrethrin II. a like compound, C 2 2 H 2 8 O 5 , obtained and used similarly.Discover...
(Stelzer and Gordon 1984). In a human study, alterations to theimmune systemcould be detected early (1–3 days) after the application of a pyrethroid-based insecticide, but 6–12 months later these changes were no longer detectable (Hadnagy 2003). Based on these studies as well as other ...