Postoperative nausea and vomiting (PONV) is a common complication of general anesthesia and less often of regional anesthesia. An algorithm for managing PONV is presented in Figure 36.1. Patients should be stratified preoperatively with regard to their risk of PONV. The incidence of PONV is higher in women, nonsmokers, and patients with a history of PONV or motion sickness and when nitrous oxide and volatile anesthetics are used under general anesthesia. Certain types of surgery (cholecystectomy, laparoscopy, and gynecologic) may also increase the risk for PONV.