48 cases of endometriosis were treated with the Neiyi (ectopic endometrium) No. 2 Pills [symbol: see text] 2 [symbol: see text]) composed of fresh Dahuang (Radix et Rhizoma Rhei), Biejia (Carapax Trionycis) and Taoren Shuang (powdered Semen Persicae). After 3 months of treatment, high effective rates were obtained in menorrhalgia, dyspareunia, proctalgia, hysteromyoma, ovary cyst, and tubercles in the pelvic cavity, with a pregnant rate of as high as 26.7% in sterility. Meanwhile, the levels of plasma PGF2 alpha and PGE2 markedly dropped, while that of 6-keto-PGF1 alpha, beta-EP, and HYP significantly elevated.