Abstract: Three preparations,alkaloid,ethanol extract and flavonoid,prepared from the Sophora feavecens Ait (Sophora angustifolia)were evaluated in vitro for antigiardia effect.The lethal concentrations of the 3 agents were 2.5mg/ml,0.5mg/ml and 5mg/ml respectively on the 72nd hour after cultivated with G.lamblia trophozoites.When their concentrations were 0.5 mg/ml,0.25mg/ml and 2.5mg/ml respectively,the growth of the trophozoites was inhi-bited.No antigiardia effect could be found as their concentrations were 0.05 mg/ml,0.05 mg/ml and 0.5mg/ml respectively.In comparison of the effects of the agents with that of mitronidazole,a similar antigiardia effect was observed.The present results support the clini-cal therapy for giardiasis by using the herb Sophora feavecens Ait.

Key words: Giardia lamblia, Sophora feaveeens Ait, flavonoid, ethanol extract, alkaloid