Long-term diarrhea, it is recommended to do a colonoscopy to exclude ulcerative colitis, irritable bowel syndrome, intestinal tuberculosis and other diseases. 1. Irritable bowel syndrome: mainly due to dietary habits or emotional and psychological factors, often manifested as a significant increase in the number of stools, mainly in loose stools, accompanied by abdominal pain, abdominal pain can be relieved after defecation. 2. Ulcerative colitis: mainly due to immune dysfunction leading to ulcerative lesions in the intestinal tract, its main manifestations are recurrent mucus, pus and blood stools, as well as diarrhea, abdominal pain, and so on. 3. Intestinal tuberculosis: Mycobacterium tuberculosis causes chronic specific infection of the intestinal tract, manifested by low fever, night sweats, fatigue, emaciation, diarrhea and constipation and other symptoms, the feces is paste or dilute watery, no pus and blood. Long-term diarrhea need to consult the doctor in time, do the relevant tests, such as routine stool tests, enteroscopy, histopathological biopsy, etc. to clarify the specific causes for targeted treatment.