Nausea and vomiting are frequent problems in the postoperative period. The introduction of 5-HT3 receptor antagonists has stimulated interest and research in this area. The paper reviews the etiology, physiology, prophylaxis and treatment of postoperative nausea and vomiting. Before using specific antiemetic prophylaxis it is important to evaluate patient risk factors, surgical stimuli and method of anaesthesia. The choice of antiemetic drugs for treatment and prophylaxis should be guided by consideration of effect mechanism, side-effects, clinical documentation and total costs. No single drug is fully effective and combination therapy should be considered in resistant cases.