Colonic distention is a common cause of ulcerative colitis (UC), an inflammatory disease of the rectum or colon of unknown origin. It mainly involves the rectum, sigmoid colon and descending colon and is characterized by mucosal congestion, edema, multiple superficial ulcers, advanced wall thickening and luminal narrowing with polyp formation. The disease is characterized by persistent diarrhea, mucus stools, bloody or purulent stools, abdominal pain and urgency, and may be accompanied by extraintestinal manifestations such as fever, anemia, arthritis, skin lesions and liver disease. The onset of the disease is rarely acute, but most of them have a slow onset and a long course, often with recurrent episodes of variable length, also known as chronic non-specific ulcerative colitis. In the early stages, abdominal pain, diarrhea and bloody stools may occur. Abdominal pain of varying degrees is caused by spasm of the colonic muscles, distension of the colon and inflammation stimulating local sensory nerves. Abdominal distension is mostly confined to the left lower abdomen or lower abdomen, with paroxysmal mild pain. When the lesion is severe, it may present with colic. Diarrhea or constipation, the symptoms are mild at the beginning of the disease, there is mucus on the surface of the stool, later the number of bowel movements increases, in severe cases, 10-30 times a day, the stool is often mixed with pus, blood and mucus, and may be paste-like soft stool. Blood in the stool is a common symptom, mainly due to local ischemia of the colonic mucosa and an increase in the activity of fibrinolysis. It is usually a small amount of blood in the stool, but in severe cases, it can be a large amount of blood in the stool or bloody water-like stool. The abdominal pain is mostly confined to the left lower abdomen or lower abdomen, or may not be present in mild cases, but may increase with the development of the disease and may be relieved after defecation. The posterior urgency is due to inflammatory irritation of the rectum, and there is often sacral discomfort. Indigestion often manifests as anorexia, fullness, belching, epigastric discomfort, nausea, vomiting, etc. Systemic manifestations are seen in patients with acute fulminant severe disease, fever, water-electrolyte imbalance, vitamin, protein loss, anemia, weight loss, etc. Prevention methods: 1. Pay attention to a moderate diet to prevent intestinal infections. 2, psychological treatment and diet control for patients. 3, abdominal pain and diarrhea, it is appropriate to eat less residue, easy to digest, low-fat, high protein. Some intolerant foods such as shrimp and crab, milk, peanuts, etc. should be avoided as much as possible. 4, avoid eating spicy frozen, cold food, quit smoking and alcohol. Prevention after the disease (prognosis): mild and moderate patients have a better prognosis, heavy and violent patients are prone to combined gastrointestinal bleeding and shock, especially acute colonic dilatation, high mortality and poor prognosis. Those with chronic persistent, long-term diarrhea and extensive lesions should be aware of the occurrence of colon cancer.