The effect of domperidone, a peripheral dopamine receptor antagonist, has been studied in the aspirin, phenylbutazone and reserpine induced gastric ulcers in rats. The gastric anti-ulcer activity of domperidone was evident following a single dose as well as a 5-day pretreatment against all the three ulcerogenic drugs. However, the protection in the five-day pretreatment group was greater than in the single dose pretreatment group. It appears that the gastrokinetic properties of domperidone play a significant role in producing this anti-ulcer effect. The study substantiates the results of the clinical observations on the healing of gastric ulcers and provides a rationale for further clinical studies in that direction. The possible mechanisms of action of this agent are discussed.