Patol churna is a well known ayurvedic formulation of Trichosanthes cucumerina Linn. (cucurbitaceae) administered in case of number of alimentary and liver disorders. It is widely used in Indian folk medicine for variety of disease conditions. The aim of present study was to evaluate the antiulcer activity of 50% ethanolic extract of patol churna (PCE) using various experimental models of gastric and duodenal ulceration in rats. Oral administration of 50% ethanolic extract of patol churna was evaluated in rats against ethanol, aspirin and pylorus ligated gastric ulcers as well as cysteamine-induced duodenal ulcers. In all the models studied, the antiulcer activity of PCE compared with that of cimetidine (100mg/kg, p.o.), an H2 receptor antagonist. PCE showed significant antiulcer activity in ethanol-induced and aspirin-induced gastric ulcer models. In 19 hrs pylorus ligated rats, significant reduction in ulcer index, total acidity and pepsin activity was observed with PCE, when compared with the control group. Mucosal defensive factors such as pH, mucin activity and gastric wall mucous content was found to be increased with PCE. PCE was also, afforded remarkable protection in cysteamine-induced duodenal lesions. The antiulcer activity of PCE was comparable with that of cimetidine. Thus, patol churna extract possess significant antiulcer activity against both gastric and duodenal ulcers in rats. The antiulcer activity may be attributed to its cytoprotective action and inhibition of acid secretary parameters.