PURPOSE: We previously reported that Panax ginseng water extract (PG-WE) played both preventive and therapeutic roles on testicular toxicity induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in animal study, one of the most potent environmental pollutants. Thus we investigated whether PG-WE might be useful in the treatment of male infertility, because men in modern society are exposed by numerous environmental hormones. MATERIALS AND METHODS: Eighteen patients with abnormal semen analysis and 8 volunteers whose semen analysis were normal as control group were enrolled in this study. Before PG-WE administration, semen analysis, hormonal study, liver and renal function test, CBC, and urinalysis were checked in all subjects. PG-WE (2.4 gm) was administered everyday for 8 weeks in both groups. Follow-up semen analysis and laboratory studies were checked at 13th week. RESULTS: In patient group semen volume was increased (2.4 1.3 ml vs 2.6 1.6 ml, p=0.051). Semen volume as well as sperm concentration in oligospermia patient were increased but not significantly. Serum estradiol level decreased by PG-WE treatment in patient group (p=0.005). All subjects showed no toxic effect. CONCLUSIONS: Our data suggest that Panax ginseng is a potential agent that can improve abnormal sperm parameters in infertile male patients and also improve the sperm quality in healthy men.