This study was attempted to investigate the effect of Ganoderma lucidum extract on digestive system in experimental animals. Ganoderma lucidum water extract (GWE) was found to be promoted the charcol transport rate in the small intestine of mice. GWE exhibited the augmentation of spontaneus movement(motility) and contractile response(tension) in the ileum and colon strips of rabbit, and these action were inhibited by atropine. GWE given intraduodenaly(i.d.) exhibited the significant increase of gastric acid secretion in pylorus-ligated rats. GWE inhibited the formation of some experimental gastric ulcers(pylorus ligation ulcer i.d., indomethacin-induced ulcer p.o., i.d. and aspirin-induced ulcer p.o.) in rats, which are considered to relate to a protective action. GWE and EtOH extract(water soluble phase) were remarkably increase of bile excretion, when administration of i.d., intravenation(i.v.) and per os (p.o.) compared with normal-control group. GWE was observed antibacterial activity aginst several intestinal microoganisms and others bacteria in vitro test.