1. Bupropion (12.5-75 mg kg-1) was given intraperitoneally to rats and was found to decrease the food consumption of the animals dose-dependently. While phenoxybenzamine, propranolol and methergoline failed to antagonize the anorectic effect of the drug; pimozide a dopamine receptor blocker decreased anorexia induced by bupropion. 2. Bupropion (12.5-50 mg kg-1) also caused a marked increase in locomotor activity of the rats. The increase in locomotion produced by bupropion was completely antagonized by pretreatment of the animals with pimozide and reserpine plus a-methyl-p-tyrosine, but not by pretreatment with phenoxybenzamine, propranolol or methergoline. 3. Taking into considerations the evidences of dopaminergic properties of bupropion shown by the others, it could be suggested that the anorexia and hyperactivity produced by bupropion may be induced through the indirect dopaminergic mechanism.