To investigate the effect of Korean red ginseng (KRG) on male sexual function and serum lipid level, the results of KRG treatments were compared to placebo group. A total of 35 patients with psychogenic impotence were assigned to medication group with KRG (n=28) and placebo (n=7). KRG and placebo were given to each group for 2 months. Changes in symptoms such as frequency of coitus, morning erection, penile rigidity and tumescence were significantly higher in the group receiving KRG than placebo group. The overall therapeutic efficacies on erectile function were 67% for KRG group and 28% for placebo group (p <0.05). In the group treated with 9 tablets of KRG, there was tendency of better efficacy as compared to the group treated with 6 tablets of KRG. The level of serum high density lipid- cholesterol (HDL-cholesterol) was significantly elevated (p < 0.05) while the other serum lipid such as total cholesterol, tiglyceride and low density lipid-cholesterol (LDL-cholesterol) , were not changed after administration of KRG. This effect was observed significantly in the group in which KRG exerted its effect on sexual function(p < 0.05). From the above results, the administration of Korean red ginseng has shown to have superior of facts as compared to the placebo. The tendency of good effect was increased when a large amount of KRG was administered. The mechanism of KRG in improving sexual function would be the result of elevating the level of geum HDL-cholesterol in impotent patients. The effect of KRG was produced when the level of cholesterol was high before starting KRG medication. Therefore, the effect of KRG could be observed more intensively when the patients have high serum cholesterol level.