Bupropion is an antidepressant and smoking cessation aid. Limited toxicological information exists for intentional and unintentional bupropion-only exposures. A retrospective review of all bupropion-only exposures reported to the Toxic Exposure Surveillance System from 1998 through 1999 was conducted. Data for the three bupropion products, Wellibutrin, Wellbutrin SR, and Zyban, included demographics, reason for exposure, clinical effects, therapy, and medical outcome. A total of 7,348 bupropion-only exposures were reported: 56% female and 61% unintentional. The majority of exposures involved Wellbutrin SR; however, Wellbutrin exposures involved a higher percentage of intentional overdoses and serious clinical effects. Clinical effects related to bupropion were noted in 2,247 (31%) exposures; 8% of all children <6-years-old compared to 46% of all teenagers. Seizures developed in 15% of all intentional exposures., Cardiovascular disturbances were extremely uncommon after overdose. The majority of unintentional bupropion-only exposures result in minimal or no clinical toxicity; however, a significant number of intentional overdoses result in seizures. (C) 2002 Elsevier Science Inc.