Abstract: AIM　To study the effect of ginsenoside Rb₁ on mouse sexual function and its mechanism. METHODS　Male mice were treated with Rb₁(2.5, 5.0 and 10.0 mg.kg^-1, ip) for three weeks, their sexual behaviors(mounting, mating) were assessed every day. After final treatment, plasma testosterone and cGMP and NO concentration in mice corpus cavernosum were measured by radioimmunoassy and spectrophotometry; Rabbit corpus cavernosum(RCC) segments were incubated with Rb₁(0.05, 0.5 and 5 μmol.L^-1). The formation of cGMP was stimulated with 10 μmol.L^-1 sodium nitroprusside(SNP), and the cGMP level was measured as above. RESULTS　Rb₁(5.0, 10.0 mg.kg^-1) significantly increased the mounting and mating numbers and serum testosterone level in vivo. The cGMP and NO concentration in MCC were dose-dependently increased after 3 weeks treatment. Rb₁(0.05, 0.5, 5 μmol.L^-1) was shown to dose-dependently enhance the cGMP level in incubated RCC in the presence of SNP 10 μmol.L^-1. CONCLUSION　These results demonstrate that Rb₁ improved the sexual behavior of mice and this effect could be attributed to its action of increasing plasma testosterone level and the activation of NO/cGMP pathway.