In a preliminary screening of plant extracts for the antigastritic and antiulcer actions in rats, the methanol extracts of Taheebo showed positive activity in HCI . ethanol-induced gastric lesion. Among the systematic fractions of hexane, chloroform, butanol and water, the most potent $H_2O$ fraction reduced significantly HCI . ethanol-induced gastric lesion at the oral dose of 300 mg/kg. In pylorus ligated rats chloroform and butanol fraction showed decreases in the volume of gastric secretion and acid output of which effects were stronger in chloroform fraction. Further assays with hexane butanol and $H_2O$ fraction disclosed that it significantly suppressed the aspirin-induced ulcer. The butanol fraction reduced significantly acetic acid induced ulcer at the dose of 400 mg/kg. The butanol and $H_2O$ fraction reduced the malondialdehyde level in HCI . ethanol-induced gastric lesion. In pylorus ligated rats, chloroform and butanol fraction reduced the malondialdehyde level and in aspirin-induced ulcer, chloroform fraction reduced that levle. These results might suggest that the butanol and $H_2O$ fraction of Taheebo had inhibitory action in gastric lesion and ulceration through inhibition of gastric acid secretion and the decrease malondialdehyde level.