Tiquinamide (Wy 24081) is a potent inhibitor of gastric secretion and gives good protection in animals against gastric and duodenal erosions induced by stress and chemical stimuli. It reduces basal as well as stimulated acid secretion but has no anticholinergic activity and is only a weak histamine H2 antagonist, since it is substantially more potent in inhibiting basal acid-secretion than the established H2-receptor antagonists, metiamide and burimamide. Since no other pharmacological effect of tiquinamide has been detected in isolated tissues, it seems unlikely that the gastric antisecretory effect of the compound results from a direct action on the peripheral autonomic nervous system. The report from Dr. Szabo on the protective effect of dopamine agonists against duodenal ulceration suggests a possible mechanism of action for tiquinamide.