Salsolinol is a tetrahydroisoquinoline compound with opiate agonist and dopamine antagonist properties. The role of salsolinol, a minor constituent of beer, in beer-induced PRL secretion was investigated in humans and rats. Beer-stimulated PRL release was greater in women than in men; the PRL-stimulating effect of beer was not blocked by naloxone pretreatment. Administration of a solution of salsolinol or cocoa (another salsolinol-containing beverage) did not stimulate PRL secretion in normal women. In rats, administration of large doses of salsolinol ip or iv was required to raise serum PRL levels, and high concentrations of salsolinol were needed to antagonize the PRL-suppressive effects of dopamine in vitro. We conclude that salsolinol is not responsible for PRL secretion induced by beer ingestion.