Two morbidly obese patients are reported who underwent gastric bypass and suffered nausea and vomiting 1 month after the operation. Endoscopy and upper GI series showed no evidence of stomal stenosis or other mechanical cause for a GI obstruction. Control of vomiting by current antiemetic drugs such as bromopride and ondansetrone was unsuccessful. The patients were then given Remeron Soltab (mirtazapine, Organon, Brazil) 30 mg once per day orally for 2 to 8 months. Nausea and vomiting disappeared within days after beginning the medication. Stomal stenosis is the main cause of vomiting after gastric bypass. After ruling out mechanical causes, other reasons for postoperative vomiting must be considered. Mirtazapine is a noradrenergic and specific serotonergic antidepressant, which blocks the 5HT3 receptor, leading to an antiemetic effect. It has successfully been used as an antiemetic drug in patients undergoing chemotherapy. We concluded that mirtazapine may be a successful option to treat non-mechanical postoperative vomiting in morbidly obese patients after gastric bypass.