Crohn’s disease, also known as clonorchiasis, restricted enteritis, granulomatous ileitis, etc., is a granulomatous inflammatory disease of the gastrointestinal tract of unknown etiology. It is a granulomatous inflammatory disease of the gastrointestinal tract of unknown etiology, and belongs to the group of inflammatory bowel diseases (inflammatory, bowel, disease, IBD) together with ulcerative colitis. Recent studies suggest that the pathogenic factors are due to the invasion of certain pathogens into the intestinal epithelium and the subsequent autoimmune response of the body, among which Mycobacterium avium subspecies paratuberculosis, measles virus, and invasive Escherichia coli infection may be associated with the development of this disease. The lesions are characterized by segmental or jumping ulcerative lesions that can occur in any part of the gastrointestinal tract, with the ileocecal region being the most common. The disease is common in Europe and the United States, with an incidence of approximately 5/100,000. The diagnosis of Crohn’s disease includes: 1) abdominal pain, diarrhea, bloody stools, intestinal obstruction, fistulas, 2) endoscopy showing ulcers and strictures mainly in the right hemicolectomy, 3) barium X-ray capsule endoscopy or double balloon small intestine microscopy showing multiple ulcerative lesions in the gastrointestinal tract, especially in the small intestine, 4) pathology showing granulomatous lesions in the entire intestinal wall and epithelium, Crohn’s disease is insidious and has a chronic course with active and remitting phases Patients are often seen with abdominal pain and diarrhea. The abdominal pain is mostly located in the right lower abdomen or around the umbilicus, often spasmodic paroxysmal pain with abdominal tinnitus, aggravated by meals, and relieved by defecation and exhaustion. Diarrhea is mostly pasty, and pus, blood or mucus stools are rare. A more fixed mass may be found in the right lower abdomen or around the umbilicus. Complications such as intestinal fistula, intestinal obstruction, and perianal fistula are seen in some patients. Differential diagnosis of Crohn’s disease The diagnosis of Crohn’s disease requires a comprehensive analysis in close combination with clinical, endoscopic, imaging, and tissue biopsy, and reliance on one test alone can easily lead to misdiagnosis. Because the terminal ileum is the preferred site of lesions, endoscopy should generally be inserted into the terminal ileum as far as possible in patients suspected of having this disease. This disease can be considered when segmental ulcerative lesions are found mainly in the right hemicolectum. If necessary, capsule endoscopy or double balloon small intestine microscopy can be used to understand whether there are similar ulcerative lesions in the small intestine, which can help to clarify the diagnosis of this disease. The main diseases to be differentiated are intestinal tuberculosis, Campylobacter enteritis, Yersinia enterocolitica, malignant lymphoma, intestinal leukoaraiosis, ulcerative colitis, ileocecal tumor, amebic enteropathy, and ischemic enteritis. Approximately 10% of IBDs cannot be distinguished as CD or ulcerative nodes and are called indeterminate colitis (IDC). When it cannot be distinguished from other types of inflammatory bowel disease (e.g., infectious enteritis), it is called unclassifiable colitis (UCC) to show the distinction between IDC. clinically, if tuberculosis cannot be ruled out, it can be treated with an anti-tuberculosis test for 2 months first.