We previously reported that Korean red ginseng (KRG) has a relaxation effect on the smooth muscles of corpus cavernosum via nitric oxide (NO) pathway and calcium and potassium channels. However, it is suggested that the active ingredients of KRG might be different depending on the sources of preparation, and there might be differences in actions for different compositions. We first investigated the composition of KRG saponins according to the extractions of the various sources of KRG, then with these extractions the relaxation effects were evaluated in vitro and hemodynamical in vivo using New Zealand white rabbit and rat corpus cavernosum. The total compositions of ginsenoside $(G-Rb_1,\;-Rb_2,\;-Rc,\;-Rd,\;G-Re,\;-Rf,\;-Rg_1)$ in fractionated KRG saponin designated as TS-1, TS-2, TS-3 were $41\%,\;40\%,\;and\;62\%,$ respectively, and the ratios of PD saponin and PT saponin (PD/PT) were 1,55, 1.72, 2.25, and 2.61, the values of which were statistically significant. In vitro studies using the rabbit corpus cavernosal muscle strips, the KRG saponin relaxed cavernosal strips in a dose-dependent manner, and same results were observed in in vivo studies, that KRG saponin increased the intracavernosal pressure in the rat. There was difference in the efficacy according to fractionation techniques. The differences in the total contents of ginsenosides did not affect relaxation, rather PT saponin content was statistically related to the degree of cavernosal relaxation, and this action presumed to be mediated by NO pathway and calcium and potassium channels. In conclusion, KRG exerts relaxation which is a key step in erection via combination of effects on NO system or calcium and potassium channels. The efficacy of this action is different to the sources of ginseng, which is affected by the different composition of ginsenosides $(G-Rb_1,\;-Rb_2,\;-Rc,\;-Rd,\;G-Re,\;-Rf,\;-Rg_1).$ Thus the further studies on the active ingredients such as minor ginsenosides and non-saponin components of red ginseng with maximum potency should be sought.