Experimental studies were undertaken to investigate for the effect of Yijin-tang on the digestive system and isolated uterus of rats. Yijin-tang was composed of five crude drugs; Pinelliae Tuber, Aurantii nobilis Pericarpium, Hoelen, Glycyrrhizae Radix and Zingiberis Rhizoma. The results obtained from experiments with water soluble fraction extracted from Yijin-tang were as follows; Spontaneous motilities of isolated ileum of mice and rabbits were suppressed, and contraction of isolated ileum of mice and guinea-pigs induced acetylcholine, barium chloride and histamine were inhibited. The anticathartic action of mice induced by castor oil were significantly observed. The spontaneous motility of isolated uterus of rats was suppressed. Inhibitory effect of gastric juice secretion and antiulcerogenic action were significantly shown in Shay rats.