Postoperative nausea and vomiting is an adverse condition that affects a large number of patients after surgical interventions. Postoperative vomiting is a severe discomfort for patients and can be a bigger concern even than postoperative pain. Although many studies have been performed on the pathophysiology of postoperative nausea and vomiting, little has been known about it. This article reviews the risk factors, mechanisms, preventive measures, and treatment of postoperative nausea and vomiting.