Local and foreign researchers say Korea's red ginseng is effective in curing impotency in men.

A medical research team led by Choi Hyung-ki at Yonsei University said Friday that it had found a substance called 'saponin' in red ginseng that stimulates blood circulation in the penis, thereby improving erectile facility.

According to the findings, a group of patients drank 300 milligrams of red ginseng extract twice a day for three months. 58 percent of them showed an increase in circulation in the penis, compared to 22 percent in the control group.

Meanwhile, a Brazilian research team has also released similar study results during a medical conference being held in London.