For patients who require anesthesia for surgery, it is important to prepare for preoperative fasting and abstinence from food and drink, the exact duration of which varies depending on the surgical site, type of surgery, and age of the patient. For routine adult elective surgery, fasting is usually 8 hours before anesthesia, and for pediatric patients it is usually 4-8 hours before anesthesia. However, adjustments need to be made accordingly. Neonates and infants may stop eating 4 hours before anesthesia after eating a small amount of liquid food due to their intolerance of hunger. In addition, patients of any age can eat clear liquids, such as water, tea, coffee, etc., 2 hours before surgery, but if patients have gastrointestinal obstruction, gastroesophageal reflux, etc., the preoperative fasting and drinking time needs to be extended accordingly. Surgical patients need to strictly follow the preoperative fasting and drinking instructions to prevent reflux of gastric contents under anesthesia, which may lead to aspiration and threaten patients’ lives.