Generally, food stays in the body for about three days, that is, the food eaten in the stomach, duodenum, jejunum, ileum, and then to the colon, the total time of the entire migration process is about three days, in which most of the material is digested, and the undigested food is turned into stool and excreted under the action of intestinal bacteria. When there is acute diarrhea or excessive intestinal peristaltic function, the residence time of food in the gastrointestinal tract will be shortened, and there will be diarrhea and undigested food residues in the stool that comes out. If the patient is an elderly person or a patient with slow peristalsis, the time that food stays in the gastrointestinal tract will be prolonged, often causing symptoms such as constipation and abdominal distension.