Intravenous (0.5 mg kg-1) or subcutaneous (2-16 mg kg-1) administration of the gamma-aminobutyric acid (GABA) analogue baclofen resulted in a stimulation of gastric motility and secretion in the rat, anaesthetized with urethane. The motility response to subcutaneous injection was dose-related. This effect was abolished by vagotomy or atropine. There was no response to baclofen in decerebrate animals. These results indicate that systemic baclofen, probably acting at a site rostral to the brainstem, stimulates gastric motility and acid secretion by a vagally-dependent mechanism.