A multicenter uncontrolled 4-week trial of bupropion in depressed outpatients was conducted in the private practices of 25 internists, 9 family practitioners, and 3 psychiatrists. Minimum exclusion criteria were used with respect to concurrent medical ailments, age, and concomitant medications. Of the 380 patients admitted to the study, 325 were included in efficacy analyses, and 359 provided data for safety analyses. The average patient was a 51-year-old married white woman with a high school education and a skilled job. Bupropion administered in doses of 150-450 mg/day was highly effective in reducing depressive symptomatology as evaluated by the Hamilton Depression and Clinical Global Impressions scales, and the Zung Self-Rating Scale. No clinically significant bupropion-related changes in blood pressure, pulse rates, respiration rate, body temperature, or laboratory parameters were recorded; only 41 patients were discontinued due to intolerance to adverse experiences. There was a notable absence of daytime sedation, and of anticholinergic and cardiovascular side effects.