The effect of alcoholic extract of Nigella sativa was investigated in rats to evaluate the anti-ulcer activity by using two models, i.e. pyloric ligation and aspirin-induced gastric ulcer. The parameters taken to assess anti-ulcer activity were volume of gastric secretion, free acidity, total acidity and ulcer index. The results indicate that the alcoholic extract significantly (P < 0.001) decreases the volume of gastric acid secretion, free acidity, total acidity and ulcer index with respect to control.