Food is usually expelled from the body 24-48 hours after eating, and the specific expulsion time varies for different foods. The emptying time of the stomach is usually 2-6 hours, and for easily digestible foods such as porridge and noodles, the emptying time is usually about 2-3 hours. For high-protein, high-fat diets, the emptying time is usually 4-6 hours. The total time for emptying through the stomach, absorption in the duodenum, small intestine, and then to the large intestine is 1-2 days, or 24-48 hours. If the emptying time is significantly longer, more than 48 hours or even 1 week before the food is emptied, the cause needs to be identified, usually because the patient is constipated. In patients with constipation, the presence of dysmotility, organic intestinal lesions, and digestive insufficiency need to be identified and treated accordingly according to the different etiologies.