To decide when you can eat, you should first distinguish whether the patient’s condition is mild or severe acute pancreatitis, because the timing of resuming diet varies considerably between these two conditions. Patients with mild acute pancreatitis usually only need to fast for a short period of time (3 to 5 days) without enteral or parenteral nutrition. Most patients can improve significantly after 2 to 3 days of intestinal rest and intravenous rehydration, and generally fasting for 3 to 5 days, up to l week, the patient can gradually resume eating by mouth. Patients with severe acute pancreatitis are usually given parenteral nutrition first, and then enteral nutrition is resumed as soon as possible. When the patient’s abdominal pain is reduced or disappeared, abdominal distension is reduced or disappeared, and intestinal dynamics are restored or partially restored, open diet can be considered. At first, the patient can first eat a moderate amount of fluid juice containing sugar (sugar and salt water, vegetable soup, fresh juice containing vitamins, etc.), then low-fat, low-protein diet (porridge, cereal, noodle soup, rice paste, etc.), and finally transition to a light diet (temporarily do not eat greasy, fried food).