Abstract： AIM　To observe the effect of artesunate on content of progesterone, estrogen and decidua of pregnant rats and study the efficacy and mechanism of artesunate for termination of early pregnancy. METHODS　Serum content of progesterone, estrogen and TNF-α were measured with RIA. The effects of artesunate on the ovary, decidua and fetus of pregnant rats were studied using histochemistry techniques. Decidual cells were estimated using cell culture. RESULTS　Artesunate 40 mg*kg-1 sc on day 6-10 of gestation significantly decreased the concentration of serum progesterone in early pregnant rats; decidual cells and fetus of treated groups were found to be degenerated at d 11. Artesunate was shown to directly damage the decidual cells. Cultured human decidual cells were exposed to artesunate for 48 h, the LC50 was found to be 25±3 mL*L-1. CONCLUSION　The damage of artesunate on decidua and placenta may be the mechanisms of its contragestational action.