OBJECTIVE Calotropis procera is a wild growing plant with multifarious medicinal properties. The present study was carried out to evaluate the effect of dried latex (DL) of Calotropis procera and its methanol extract (MeDL) against gastric ulcers induced in rats. METHODS Aqueous suspension of DL (20 and 100mg/kg) and MeDL (10 and 50mg/kg) were given orally to 36h fasted rats and ulcers were induced by ethanol, pyloric ligation and aspirin. Parameters like ulcer score and levels of oxidative stress markers were measured in all the models. The effect on gastric hemorrhage and tissue histology was studied in ethanol model and on acidity, pH and volume of gastric secretion was evaluated in pyloric ligation model. The protective effect of DL and MeDL was compared with that of standard anti-ulcer drug famotidine (20 mg/kg). RESULTS DL and MeDL produced 85-95% inhibition of gastric mucosal damage in ethanol model and 70-80% inhibition in aspirin model. The protective effect of these extracts was associated with marked reduction in gastric hemorrhage, maintenance of tissue integrity and normalization of levels of oxidative stress markers like glutathione, thiobarbituric acid reactive substances and superoxide dismutase. Like famotidine, DL and MeDL decreased the gastric acidity from 376.17+/-21.47 mequiv./l to 163.88+/-6.86 and 201.48+/-8.86 mequiv./l respectively in pyloric ligation model. These extracts increased the gastric pH without affording any protection to gastric mucosa in this model. CONCLUSIONS The latex of Calotropis procera has the therapeutic potential to relieve gastric hyperacidity and to prevent gastric ulceration induced by necrotizing agents.