[Literature research on Changshan (Radix Dichroae)]

Originally named Hengshan, it is recorded firstly in the Shen nong ben cao jing(Shennong's Classic of Materia Medica). Its name is changed as Changshan in the Song Dynasty and still used today. Changshan is a cosmopolitan species, and the producing area expands from Sichuan, Hubei, Shaanxi and Henan during the Wei and Jin Dynasties to nowadays more than 10 provinces, such as the south of the Yangtze River, Gansu etc. Before the Tang Dynasty, Changshan's original plant is Orixa japonicaThunb., which is changed to Dichroa febrifugaLour. from the Song Dynasty as its main orthodox product.