In order to study effects of Korean ginseng (Panax ginseng C.A. Meyer) saponin fraction on polyamine metabolism in rat organs, Korean ginseng saponin fraction was administrated to rats for 1, 2, 3, 4, 6 and 12 months and brain, liver, prostate, spleen and testis were removed from these rats. Two enzyme activities were measured from those organs; ornithine decarboxylase (ODC), which is a regulatory enzyme of putrescence biosynthesis and S-adenosylmethionine decarboxylase (SAMDC), which is also a regulatory enzyme of spermidine and spermine biosynthesis. The amounts of polyamine were also determined. As for prostate and testis organs, Korean ginseng saponin fraction was innocuous for ODC and SAMDC activities from rats fed for 1 and 2 months. However, after 3 months, the stimulatory effect on the activities of two enzyme gradually increased in test groups and reached its maximum in 12 months. The contents of spermidine and spermlne of test groups in prostate and testis were also much higher than those of control groups. Another stimulatory effect on the activities of two enzymes was observed in liver and reached its maximum in 6 months. In the other organs such as brain and spleen, the enzymes were turned out to be not affected by feeding Korean ginseng saponin fraction. From the cumulative results, the stimulatory effect of Korean ginseng saponin fraction on polyamine metabolism was observed in prostate, testis and liver.