Parthenium hysterophorus L. (Asteraceae) is a serious weed of pastures, wasteland and agricultural fields in world. Various problems are posed by the weed to human health, biodiversity agriculture and live stock production. It is used as folk remedy against various afflictions. Parthenium owes its several prominent biological activities to several important chemical compounds like histamine, saponin, glucosides and triterpene (sesquiterpene). The book reports the toxicological and biochemical effects of the plant extract on rats.