The metabolic fate of the anti-Parkinsonian drug budipine was studied in rats after oral administration. The presence of an aromatic hydroxylation product, metabolite M1, and its O-sulphate conjugate was confirmed. Three new minor metabolites, budipine N-oxide, metabolite M1 N-oxide and a secondary metabolite derived from M1 via hydroxylation of a methyl of the tert-butyl group, were isolated and identified in rat urine. The presence of a metabolite M1-glucuronic acid conjugate, was also established through different enzymatic treatments of the rat urine.