Pyrethrum refers to several Old World plants of the genus Chrysanthemum (for example, C. coccineum) which are cultivated as ornamentals for their showy flower heads. It is also the name of a natural insecticide made from the dried flower heads of C. cinerariifolium and C. coccineum. Pyrethrum was used for centuries as an insecticide. and as a lice remedy ("Persian Insect Powder," "Persian Pellitory") in the Middle East. It was sold worldwide under the brand Zacherlin by Austrian industrialist J.… (More on Pyrethrum)