The present experiment was carried out to investigate the effects of Panax Ginseng on the phagocytic function of reticuloendothelial system in rats. The phagocytic activity was assessed by carbon clearance method after intraperitoneal administration of ginseng extract with various dosage, namely 1, 5, 10, 20, 50mg per 100gm of body weight, respectively. The obtained results were followings : 1) In small dosage-treated group (1mg/100gm of B.W.), there were no significant differences in phagocytic activity between treated and control group. 2) In large dosage-treated group(5, 10, 20 & 50mg/100gm of B.W.), the phagocytic activity showed an increased level by time of twelve hours after injection except temporary suppression on one hour after injection. Thereafter it returned gradually to the normal level by the time of twenty-four hours. From these results, it was concluded that the phagocytic function of reticuloendothelial system was increased by the administration of appropriate dosage of ginseng extract.