Abstract: Tithonia diversifolia(Hemsl.) A. Gray (Compositae) is an American plant which has become naturalization in the south of China. In Yunnan, it is mainly distributed on small hills of torrid zone with an altitude from 500 to 1600 meters above sea level. The leaves have been used as an agent for subduing swelling, dissolving lumps and treating enteritis and gastritis in local folk medicine (云南省药材公司，1993). Previous report showed that T.diversifolia was rich in sesquiterpene lactones (Raghwendra et al, 1976). However, the plant distributed in Yunnan has not been studied yet......

Key words: Tithonia diversifolia, Sesquiterpene lactones