This study was attempted to investigate the effect of Machili Cortex extract(Machilus thunbergii Sieb. et Zucc. ) on digestive system in experimental animals. EtOH and MeOH extracts(E.E. and M.E.) were found to inhibit the charcoal transport rate in the small intestine of mice. E.E. exhibited the inhibition of spontaneous movement(motility) and tension in the ileum and colon strips of rabbit, and these actions were inhibited by action of acetylcholine. E.E. and M.E. given intraduodenaly(i.d.) exhibitied the significant decrease of gastric acid secretion in pylorus-ligated rats. E.E. and M.E. inhibited the formation of some experimental gastric ulcers(pylorus ligation-ulcer i.d., indomethacin-induced ulcer p.o. and aspirin-induced ulcer p.o. ) in rats, which are considered to relate to a protective action. E.E. and M.E. caused remarkable increase of bile excretion, compared with normal-control group, when adminstered through i.d., i.v. and p.o. The antibacterial activity against several intestinal microorganisms and other bacteria in vitro test was observed in the administration of E.E. and M.E.