Inflammatory disease of the colon characterized by extensive ulceration of the colonic mucosa is called ulcerative colitis, also known as chronic non-characteristic ulcerative colitis. The lesions mostly involve the rectum or distal colon, but may also invade the entire colon. The disease can develop in people of any age, but is more common in people aged 20 to 40. I. Etiology The etiology of this disease is not clear, but there are many factors related to its development, such as germs, viruses, fungi and focal infections, which are considered to be causative factors. Infection theory believes that: the germs in the intestine are mostly secondary to invasion, causing infection and septicemia and mucosal destruction. The lysozyme theory believes that: lysozyme and mucinase are the primary factors, and the increased concentration of lysozyme in the stool of patients with ulcerative colitis can dissolve the mucus protecting the surface of the intestinal mucosa, exposing the intestinal mucosa to feces and causing secondary infection. It is also believed that: the influence of mental factors can cause changes in the intestinal mucosa and even ulcers; in addition, allergic reactions to food or other substances, allergic reactions, disorders of the vegetative nerves of the colon, lack of nutrition, metabolic disorders, as well as autoimmune and genetic factors, may be related to the development. The main symptoms of ulcerative colitis are diarrhea and feces with blood and mucus. The urgency of the onset, the severity of symptoms, and the development or remission of the disease are very inconsistent. (a) Acute phase: moderately elevated body temperature, systemic toxicity, loss of appetite, weakness, vomiting, abdominal distension, dehydration, diarrhea, and posterior urgency; in patients with extensive and severe lesions, there are often abdominal cramps (obvious in the left lower abdomen), relief after defecation, and pus, blood and mucus in the feces. (II) Chronic phase: abdominal pain and diarrhea are not obvious, only scanty stool or constipation, blood in stool or occasional history of tarry stool. (C) remission phase: diarrhea can disappear, abdominal pain is not obvious, there are often 3 to 4 atheromatous stools, and symptoms such as malnutrition, anemia and weight loss.