The effect of different extracts of leaves and fruits of Moringa oleifera Lam. (Moringaceae) on gastric and duodenal ulcers was evaluated by using different gastric ulcer models and cysteamine-induced duodenal ulcer method. The leaf extracts (500 mg=kg, p.o.) of Moringa oleifera showed gastric ulcer healing effect in acetic acid-induced chronic gastric ulcers. The acetone extract and methanol extract of the leaves produced gastric antisecretory effect in pylorus-ligated rats and showed gastric cytoprotective effect in ethanol-induced and indomethacin-induced gastric ulcers. The leaf extracts also produced a significant reduction of stress-induced gastric ulcers and cysteamine-induced duodenal ulcers. None of the extracts of the fruits showed any significant antiulcer effect. It was concluded that leaves of Moringa oleifera increase healing of gastric ulcers and also prevent the development of experimentally induced gastric ulcers and duodenal ulcers in rats.