This study has been undertaken to investigate the effect of methanolic extract of leaves of Jatropha curcas Linn. (JC) on pylorus ligation and Aspirin-induced gastric ulcers in Wistar rats. 30 albino wistar rats of either sex were selected and divided into 5 groups of 6 animals each. Gastric lesions produced by pylorus ligation (PL) plus aspirin (200mg/Kg, PO). Treatment with JC extract of (100 mg/Kg bodyweight, 200 mg /Kg body weight) and ranitidine (50 mg/Kg body weight) for 6 days to the aspirin and PL rats were given and absorb the acid parameters.A significant dose dependant reduction (P < 0.05) in the acid parameters like gastric volume, pH, total acidity, total acid output, total proteins and ulcer index were observed after treatment with 100 mg, 200 mg JC extracts in PL plus aspirin induced ulcers compared to the normal PL rats. Histopathological examination of stomach mucosa showed the protective action of JC extracts against mucosal epithelial damage caused by aspirin. The present study provides a strong evidence of antiulcer activity of JC extract against gastric lesions. The antiulcer activity is recognized by a reduction in acid-secretary parameters (i.e. total and free acid), gastric volume and ulcer score suggesting that acid inhibition accelerates ulcer healing, thereby strengthening of mucosal barrier. © 2011 Elsevier B.V., All rights reserved.