The effect of ginseng on the reactivity of penile corpus cavernosal smooth muscle strips of rabbits was investigated to support the clinical application of ginseng for the treatment of erectile dysfunction. New Zealand white rabbits were randomly divided into two groups, normal diet group (n=9) and ginseng saponin diet group (n=5). Then, each group was fed normal diet and Korean red ginseng saponin diet (50 mg/kg/day) for 10 weeks. We measured concentration dependent relaxation of corporal smooth muscle to acetylcholine (10-8 M to 10-4M) in organ chamber. The degree of relaxation was expressed as percentage of maximal relaxation obtained by papaverine (10-4M). Dose dependent relaxation of corpus cavernosal smooth muscle to acetylcholine, at the concentration of 10-8 M to 10-4M by half log increment, was 4.06$pm$0.00, 4.30$pm$1.30, 5.32$pm$0.68, 11.64$pm$1.74, 16.24$pm$1.61, 23.33$pm$ 2.29, 26.45$pm$2.25, 30.43$pm$2.40 and 33.41 $pm$2.48 (%), respectively in normal diet group and 9. 83$pm$4.15, 20.60$pm$4.62, 24.1815.12, 35.75$pm$5.71, 43.35$pm$6.11, 51.30$pm$6.22, 56.33$pm$6.22, 54.30$pm$4.17 and 51.98$pm$3.92 (Vc), respectively in ginseng group. These data suggest that ginseng enhances ondothelium-dependent acetylcholine-induced relaxation of penile corpus cal.ernosal smooth muscle in rabbits.