Salacia lehmbachii is being used in traditional medicine for the treatment of gastric ulcer, this claim has not been scientifically substantiated or refuted. This work was therefore, designed to validate the antiulcer potential of the aqueous root bark extract of S. lehmbachii on stress induced and ethanol induced gastric lesions in rats. Phytochemical analysis and acute toxicity studies were also carried out. The extract (200 and 400 mg/kg) exhibited significant and dose dependent antiulcer effect in both models. The ulcer protection effect of the root extract is comparable to ranitidine. The root bark extract was found to be non toxic up to 5000 mg/kg dose level in rats. Phytochemical analysis identified flavonoids, tannins, saponis, alkaloids, terpenoides and flavonoids. The study provides strong evidence of antiulcer activity of S. lehmbachii aqueous root bark extract against gastric acid ulceration in rats