Banned amphetamine-based anorectics are illicitly imported into the United States (US), but little is known regarding the harm these diet pills pose to US residents. A 26-year-old woman using imported diet pills presented with a two-year history of intermittent chest pains, palpitations, headaches and insomnia. Urine toxicology screen detected amphetamines and benzodiazepines. Fenproporex and chlordiazepoxide were detected in her pills. Her symptoms resolved after she stopped using diet pills. A 38-year-old man using imported diet pills presented after his occupational urine screen was significantly positive for amphetamine. Fenproporex and fluoxetine were detected in his pills. These cases illustrate the potential harm from imported prescription diet pills that combine fenproporex with benzodiazepines, antidepressants, diuretics, laxatives and other substances. Increasing physicians' awareness of imported diet pill use may improve care of patients suffering from the pills' many adverse effects.