Ibopamine, a peripheral dopamine agonist, was administered to 80 postpartum women to assess its effect on prolactin (PRL) and milk production. The acute administration of 400 mg significantly decreased serum PRL for more than 240 min. Women given ibopamine 400 mg t.d.s. for 5 to 10 days showed suppression of PRL and milk letdown was prevented in the latter group. No side effects were observed on repeated administration. Ibopamine may be a useful alternative to other dopaminergic compounds for the inhibition of puerperal lactation.