The multiglycosides of Tripterygium uilfordii（TII）

a ready-made Chinese herbal medicine used for the treatment of rheumatoid arthritis

have been shown to cause oligospermia in patients. In the present study

the antifertility effects of TII and tripchlorolide （T4

isolated from TII） were observed in male rats. In rats fed with TII at a dose of 10mg·kg·d for 7 weeks

the seminiferous tubules were essentially not influenced. However

most of the sperm heads along the surface of the tubular lumen were transformed from the normal sickle-shaped to round shaped. suggesting a possible mutagenic action. There was minimal testicular change but prominent epididymal spermatozoa damage in all rats treated with T4 （0. 05 mg·kg·d） for 7 weeks. The epididymal spermatozoa showed various structural abnormalities

including disrupted connecting pieces and cracked midpieces. and more than 80% of the spermatozoa were decapitated. No significant changes were seen in the main visceral organs. The data suggest that T4 may have good prospects as a male contraceptive.