Pre-operative fasting and water fasting is designed to improve surgical safety to avoid phenomena such as patient vomiting resulting in aspiration. Most of the surgeries are performed under general anesthesia, in general anesthesia, because of the effect of anesthesia drugs, the protective reflex choking will be weakened or even disappeared, so elective surgery patients, preoperative fasting will play a protective role in a planned. Preoperative fasting for various foods and beverages is different in time, for example, clear drinks should be prohibited for a minimum of 2h, breast milk for 4h, infant formula for 6h, milk and other liquid dairy products for 6h, starchy solid foods for 6h, fried or fatty and meaty foods for 8h. Preoperative fasting will reduce the burden on the digestive tract, avoiding symptoms such as vomiting and serious problems such as aspiration.