Asthma to tetramethrin.

P yrethrum is extracted from the flowers of Chrysanthemum cinerariifolium (botanic family of Compositae) ( 1). The active components of pyrethrum are esters of chrisanthemic and pyrethric acids (i.e., pyrethrins, cinerins, and jasmolins), which are collectively referred to as pyrethrins. Pyrethrum and pyrethrins have been used since the early 19th century for control of indoor insect pests as well as for direct application to man and animals. Synthetic analogs, termed the pyrethroids (e.g., permethrin, allethrin, tetramethrin, and permethrin), have been developed to enhance insecticidal activity and photostability. [...