Bupropion is a trimethylated monocyclic phynylaminoketone that is an effective antidepressant in humans. It neither is sedating, anticholinergic, nor cardiotoxic. Its mechanism of action may be related to dopamine, but remains uncertain at this time. Clinical trials comparing bupropion 300-750 mg/d with placebo show it to be superior to placebo in efficacy and as well tolerated. Bupropion, in controlled clinical trials, is as effective as amitriptyline or imipramine, with fewer side effects. The only clinically significant adverse reaction to bupropion in more than 1000 patients studied has been seizure induction at a frequency comparable with that of imipramine. Bupropion appears to be safe and effective in both adult and geriatric depressed patients. Although it appears to be safer and equally efficacious when compared with currently used antidepressants, it has not been tested by routine clinical use.