Ulcerative colitis is a chronic nonspecific inflammatory disease of the colon and rectum of which the etiology is not well understood. The lesions are confined to the mucosa and submucosa of the large intestine and are predominantly ulcerative. The lesions are mostly located in the sigmoid colon and rectum, but may also extend to the descending colon or even the entire colon. The course of the disease is long, mild or severe, and often recurrent. The disease can be seen at any age, but is most often seen in young adults. The pathogenesis of ulcerative colitis is mainly: 1. immune factors: most patients have immune diseases; 2. genetic factors: the incidence of the disease varies significantly between races, and recent studies have shown a genetic correlation; 3. infectious factors: pathogenic microorganisms may be non-specific promoters of its development; 4. psychoneurological factors: the disease can be triggered by stress and exertion. The clinical manifestations of ulcerative colitis are: 1. Gastrointestinal manifestations: diarrhea, abdominal pain, abdominal distension, nausea, vomiting, loss of appetite, pressure pain in the left lower abdomen, etc. In severe cases, abdominal muscle tension and rebound pain may occur, at which time one should be alert to complications such as colonic dilatation and intestinal perforation. 2. Systemic symptoms: fever may occur in the acute stage, and high fever is often seen in severe cases; weakness, emaciation, anemia and hypokalemia may occur if the disease persists, and hypokalemia is especially likely to occur. 3, extra-intestinal manifestations: arthritis, erythema nodosum, iritis, ankylosing spondylitis, recurrent oral ulcers, etc. Colonoscopy is an important test for the diagnosis of ulcerative colitis, which allows direct observation of intestinal mucosal changes and accurate understanding of the extent of the lesion. In addition, routine blood, stool examination and X-ray examination are also important tests. The treatment of ulcerative colitis includes: 1. general treatment: pay attention to rest, work and rest, diet should be less slag easy to digest, balanced nutrition, adequate calorie intake, reduce fat intake, avoid cold and irritating food; 2. medication: 1) aminosalicylic acid preparations: salazopyridine, mesalazine enteric soluble tablets, the initial dose increased, maintenance treatment can be reduced, the course of treatment is generally 1-2 years, taking salazopyridine 2) Glucocorticoids: the basic effect is non-specific anti-inflammatory and suppression of immune response, suitable for heavy or fulminant type; 3) Immunosuppressants: azathioprine, methotrexate, cyclosporine, etc. In case of untimely treatment, surgical treatment should be considered in case of cancer, intestinal perforation and colonic dilatation. Ulcerative colitis should be treated thoroughly to avoid recurrent attacks. Usually should pay attention to dietary hygiene, regular life, reduce allergic food level damage intestinal drug intake, reduce mental burden and mental trauma, to avoid the occurrence of infectious diseases.