The aim is to explore the mechanism of Gonghuanzhixue Pian treating endometrorrhagia caused by Cu-IUD. In constrast with indomethacin, we investigated the effects of Gonghuanzhixue Pian on the content of NO and activity of the NOS in uterine tissues of Cu-IUD-wearing rabbits. The results show that Gonghuanzhixue Pian can decrease the content of NO and activity of NOS and influence the constrictive function of the spirartery in the uterine of rabbits wearing Cu-IUD The results suggest that endometrorrhagia caused by CuIUD-wearing can ...