Diarrhea is mainly considered to be caused by gastroenteritis, irritable bowel syndrome, intestinal tumor and other factors. 1. Gastroenteritis: when patients eat unclean and indigestible food, it leads to edema of the intestinal wall, abnormal gastrointestinal peristalsis, and intestinal dysfunction, which results in diarrhea, abdominal pain, nausea, vomiting and so on. 2. Irritable Bowel Syndrome (IBS): when the patient’s mood fluctuation is obvious and the pressure of life and work is high, the patient will also suffer from digestive discomfort, diarrhea, nausea, vomiting and so on. 3. Tumor of digestive tract: when patients have tumors of digestive tract such as colorectal cancer, stomach cancer, etc., diarrhea will also occur due to tumor stimulation of digestive tract and acceleration of gastrointestinal peristalsis. In addition, there may be other reasons for diarrhea, so it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or therapy under the guidance of the doctor.