Chronic diarrhea can be caused by infectious chronic enteritis and non-infectious chronic enteritis (such as ulcerative colitis, Crohn’s disease, etc.) and other diseases, the clinical manifestations of the different diseases have a slight difference, such as infectious chronic enteritis can have diarrhea, nausea and other symptoms, ulcerative colitis can have diarrhea, mucus and blood in the stools, and Crohn’s disease can have abdominal pain, diarrhea and other symptoms. 1. Infectious chronic enteritis: mainly due to bacterial, parasitic, viral infections after the disease is prolonged, can have nausea, vomiting, diarrhea, abdominal pain and other symptoms. 2. Ulcerative colitis: it is a chronic non-specific inflammatory disease of the rectum and colon whose etiology is not yet completely clear, which may include diarrhea, mucous bloody stools, pain in the lower abdomen, acute and post-traumatic stress (uncomfortable in the lower abdomen, wanting to relieve stools very much, and feeling of incomplete defecation after defecation), and other symptoms, and weight loss may occur in the case of long-term illness. 3. Crohn’s disease: the cause of the disease is not yet completely clear, can involve the entire digestive tract of chronic inflammatory granulomatous disease, diarrhea, abdominal pain, fatigue, weight loss, low-grade fever and other symptoms, mucus blood stools are usually not as obvious as symptoms of ulcerative colitis. When chronic diarrhea symptoms occur, it is recommended to go to the hospital and ask the doctor to make a judgment and clarify the cause of the disease.