It is an intestinal inflammatory disease of unknown cause, which can occur in any part of gastrointestinal tract, but usually occurs in the terminal ileum and right colon. This disease and chronic nonspecific ulcerative colitis are collectively called inflammatory bowel disease (IBD). The clinical manifestations of this disease are abdominal pain, diarrhea, intestinal obstruction, accompanied by fever, nutritional disorders and other parenteral manifestations. The course of the disease is prolonged and recurrent, which is not easy to cure. This disease is also called localized enteritis, localized ileitis, segmental enteritis and granulomatous enteritis.