Most species of Gentianaceae in Qinghai-Tibet Plateau are traditional Tibetan medicines which were used for stabilizing liver functions and improving the gallbladder. They were used for curing hepatitis, cholecystitis and other diseases. We have studied the chemical composition of 12 species of Gentianaceae and extracted 17 xanthone glycosides. Nine of them are new natural products. Pharmacological studies showed that xanthone C-glycosides is beneficial to the gallbladder and that xanthone O-glycosides is the effective component in curing hepatitis.