Twenty-nine species of traditional Chinese herbal medicines were collected from the market and were extracted by 50% ethanol for three times. The extracts were tested for the nitric oxide (NO) production inhibitory activity. We found six species of Gentiana Ioureiri (G.Don) Griseb.; Scutellaria barbata D. Don [S. rivularis Wall]; Securinega suffruticosa (Pall.) Rehd.; Hedyotis diffusa Willd.[Oldenlandia diffusa(Willd.)Roxb.]; Stephania tetrandra S. Moore and Aristolochia austroszechuanica Chien et C.Y. Cheng ex C.Y. Cheng et J.L. Wu. exhibite strong NO production inhibitory activity. The IC50 of these species are 13.5μg/mL、38.28μg/mL、26.12μg/mL、27.44μg/mL、43.54μg/mL and 40.78μg/mL respectively.
