The fixed oil of Ocimum sanctum L. (Labiatae) was found to possess significant antiulcer activity against aspirin-, indomethacin-, alcohol-, histamine-, reserpine-serotonin- and stress- induced ulceration in experimental animal models. Significant inhibition was also observed in gastric secretion and aspirin – induced gastric ulceration in pylorus ligated rats. The lipoxygenase inhibitory, histamine antagonistic and antisecretory effects of the oil could probably have contributed towards antiulcer activity. Ocimum sanctum fixed oil may be considered to be a drug of natural origin which possesses both anti- inflammatory and antiulcer activity.