This document discusses guidelines for preoperative fasting in patients undergoing procedures requiring anesthesia. It outlines recommendations for fasting times for various foods and liquids in adults, children, and special populations. The primary goal of preoperative fasting is to reduce the risk of pulmonary aspiration by allowing time for gastric emptying. However, prolonged fasting can increase risks of dehydration, hypoglycemia, and patient dissatisfaction. The document reviews techniques to decrease gastric volume and increase gastric pH as additional measures to prevent aspiration during induction of anesthesia.