Surgery under anesthesia poses a significant stress to the body, and postoperative complications occur in up to 20% of cases. An understanding of postoperative complications, including assessment of patients at risk, risk mitigation, early recognition, and evidence-based treatment, is essential to provide high-value health care. Common postoperative complications reviewed in this article include fever, cerebrovascular accident, nausea and vomiting, ileus, and urinary retention, including discussion of pathophysiology, prevention, and treatment.