Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the intestine of unknown etiology, mainly including ulcerative colitis (UC) and Crohn’s disease (CD). Its etiology may include environmental, infectious, immune and genetic factors. The clinical symptoms of IBD are mainly diarrhea, abdominal pain and mucopurulent blood stools, while CD mainly presents with abdominal pain, diarrhea, fistula and anal lesions, etc. IBD is quite common in western countries, and the incidence of UC is 10/100,000 to 200,000/100,000 in Europe and the United States, while the incidence of CD is 5/100,000 to 10/100,000. IBD has become a common disease of the digestive system and the main cause of chronic diarrhea in China, and the patients are mostly young adults, so it is getting more and more attention. The diagnosis of IBD is difficult because of its unclear etiology and non-specific clinical symptoms, which are easily confused with other diseases. Diagnostic methods: mainly include clinical history, colonoscopy, imaging, histological examination and serological indexes. Differential diagnosis: 1, chronic bacteriophageal dysentery often have a history of acute bacteriophageal dysentery, stool examination can isolate Bacillus dysenteriae, colonoscopy to take mucopurulent secretions culture has a high positive rate, antibacterial treatment is effective. 2, amoebic enteritis, jam-colored stools, fecal examination can find amoebic trophozoites/encapsulation, anti-amoebic treatment is effective. 3, schistosomiasis History of exposure to epidemic water, fecal examination can find schistosome eggs, hatching trichurias positive. In the acute stage, rectoscopy can reveal mucosal yellow-brown granules, and biopsy of mucosal pressure or histopathological examination can reveal schistosome eggs. 4, CD 5, colorectal cancer Most often seen in middle-aged and elderly patients, colonoscopy and X-ray barium enema examination is valuable for diagnosis. 6, IBS Mucus in stool but no pus and blood, colonoscopy without evidence of organic lesions. 7, intestinal tuberculosis lesions mainly involving the ileocecal region, positive tuberculin test or T spot test. Primary malignant lymphoma of the small intestine is often confined to the small intestine and/or adjacent mesenteric lymph nodes for a long time, and in some patients, the tumor may be multifocal. If colonoscopy reveals extensive erosion in the intestinal segment, large indentation marks or filling defects, significant thickening of the intestinal wall on MRI or CT, and enlarged abdominal lymph nodes, the diagnosis of malignant lymphoma of small intestine is mostly supported. Treatment: Internal medicine General treatment Emphasize diet and nutritional supplementation, and give high nutrition and low residue diet. Take appropriate multivitamin and trace element supplements. Give enteral and parenteral nutritional support therapy when necessary. Drug treatment 1.Aminosalicylic acid preparation: It is effective in controlling the active period of mild and moderate patients, mainly for those whose lesions are confined to the colon, and is used for long-term maintenance treatment. 2, glucocorticoids: suitable for the induction of remission in moderate to severe active IBD, not for use in the maintenance period. 3.Immunosuppressants: For active patients with poor glucocorticoid efficacy or glucocorticoid dependence, the addition of such drugs can reduce the dosage of glucocorticoids or even discontinue them, and can be used as long-term maintenance therapy. 4. Biological agents: suitable for those who are ineffective or intolerant to hormone and immunosuppressant treatment, can be used to induce remission, and can also be used for maintenance treatment. Surgical treatment Indications: Complicated hemorrhage, intestinal perforation, intestinal obstruction, fistula and abscess formation, combined with toxic colonic dilatation by active medical treatment and ineffective and with severe toxemia. Emergency surgery indications: Complicated hemorrhage, intestinal perforation, heavy patients especially combined with toxic colonic dilatation after active medical treatment and ineffective and with severe toxemia. Elective surgery indications: 1. Complicated colon carcinoma; 2. Chronic active cases with poor medical treatment and seriously affect the quality of life; or glucocorticoids can control the disease but the side effects are too great to tolerate.