Korean rheum (Rheum undulatum Linne) as one of the botanical crude drugs which belong to polygonaceae family has been extensively applied in Chinese medicine during the last decades. It has been particularly used in cathartic and gastric tonic among the folk remedies. There are, however, a few reports with regard to the pharmacological effects on the motility of intestines of several animals. The authors hereby paid attention to this point of view and made experiment to examine the relationship between the alcohol extract of Korean rhei rhizoma and the motility of the isolated rabbit intestine, making the use of several drugs related to the motility of intestine such as acetylcholine, pilocarpine, atropine, papaverine, serotonin, and barium chloride. The movement of the isolated rabbit intestine in Tyrode s solution was recorded with the electric kymograph according to the Magnus method. The results of the experiment are as follows. 1. The motility of the isolated rabbit intestine represents the tendency of gradual dilatation in proportion to the concentration of R-A 10^-4,5 X 10^-4, and 10^-3. 2. R-A 5 X 10^-4 does not seem to have the significant effect with acetylcholine, pilocarpine and atropine on motility of the isolated rabbit intestine strip. 3. R-A 5 X 10^-4 significantly blocks the contractile effect caused by serotonin 10^-6 on motility of the isolated rabbit intestine strip. 4. R-A 5 X 10^-4 significantly blocks the contractile effect caused by barium chloride 10^-4 on motility of the isolated rabbit intestine strip. 5. R-A 5 X 10^-4 significantly synergizes the dilatative effect caused by papaverine 10^-6.