This study demonstrated that bupropion hydrochloride, an effective antidepressant and a commonly used smoking cessation aid, dose-dependently caused clonic convulsions in mice, with the CD50 (convulsive dose50, i.e., the dose producing convulsions in 50% of mice) at 119.7 mg kg(-1). An evaluation for anticonvulsant effects showed that bupropion in the doses of 15-30 mg kg(-1) protected against convulsions induced by maximal electroshock with the ED50 (effective dose50, i.e., the dose protected 50% of mice against convulsions) being 19.4 mg kg(-1). Bupropion had no effect on pentylenetetrazole- and kainic acid-induced convulsions. It is possible that the anticonvulsant activity of bupropion may be exploited for use in the treatment of epilepsy but it requires further investigations.