There are many methods to examine the intestinal tract, and the following are more commonly used in clinical practice: first, physical examination, anal palpation can examine the patient’s rectum, and abdominal palpation can initially examine the rectum and colon. Secondly, laboratory tests can be performed to determine whether there is intestinal bleeding and infection by checking the stool routine and fecal occult blood test. Third, radiological examination, radiological examination includes X-ray plain film examination, chest, abdominal CT examination, magnetic resonance imaging, barium irrigation imaging, etc. Fourth, endoscopy, including proctoscopy, sigmoidoscopy, colonoscopy and capsule endoscopy, etc.