Diarrhea is usually caused by the following conditions: first, intestinal infections. Including bacterial infections, viral infections and parasitic infections, usually caused by unclean diet or lack of hygiene, manifested as sudden and severe diarrhea, accompanied by pain in the abdomen. Second, improper diet. Overeating, irregular diet or eating too much too cold, too hot, with irritating food. Third, mental factors. Long-term mental tension, anxiety or emotional instability will have a stimulating effect on cortical function, resulting in gastrointestinal function disorders. The common clinical irritable bowel syndrome. Fourth, indigestion. The digestive function of the spleen and stomach is reduced and cannot be digested and absorbed in a timely manner, and diarrhea will occur when it stays in the stomach for a long time. Fourth, intestinal diseases. The common ones are chronic bacterial disease, lymphoma, colorectal cancer, and aspiration disease.