With the improvement in living standards and changes in eating habits, constipation, diarrhea and blood in the stool have become commonplace. Many people think that blood in the stool is nothing but hemorrhoids, but if you think so too, you should be careful. If you think so too, you should be careful because many diseases may lurk quietly under the “cloak” of hemorrhoids and give you a fatal blow when you are relaxed, including “bowel cancer”. However, the symptoms of hemorrhoids and bowel cancer are highly similar, and the lesions are very close to each other, so it is difficult to make a clear diagnosis by yourself. It is necessary to use some auxiliary tests to help us find these “bad eggs” that are trying to mix with hemorrhoids. 1, the type and role of auxiliary tests (1) fecal occult blood test fecal occult blood test diagram fecal occult blood test for the diagnosis of gastrointestinal bleeding has an important value, with a chemical test to detect trace amounts of blood in the feces, invisible to the naked eye, often used as a screening indicator for the early diagnosis of gastrointestinal malignancies. The test is simple, non-invasive and more acceptable to patients. Repeated examinations are important for the screening of GI tumors and the differentiation of benign and malignant lesions, because those with malignant lesions in the gastrointestinal tract are mostly consistently positive when this test is performed. (2) Colonoscopy Colonoscopy is the use of fiberoptic colonoscopy or electronic colonoscopy, direct vision or electronic video observation and examination of the whole colon. The examination can also be performed to obtain biopsies for pathological examination, as well as to perform electrocoagulation to stop bleeding, remove polyps with tips, and remove some colonic neoplasms. The test is mainly suitable for patients with lesions such as polyps, tumors, ulcers, inflammation, and unexplained bleeding foci in the colon. The positive rate of detecting lesions in the colon is higher than that of barium enema, and it is also useful for detecting lesions in the cecum and ileocecal region and the terminal ileum. However, colonoscopy is still a relatively rare test in life, and the test may also produce some discomfort, so there are some clinical indications for colonoscopy, and patients and doctors can make judgments based on these indications to clarify whether it is necessary to perform colonoscopy. 2, colonoscopy indications (1) unexplained blood in the stool, or persistent positive fecal occult blood. (2) If there are lower gastrointestinal symptoms, such as chronic diarrhea, long-term progressive constipation, changes in stool habits, abdominal pain, abdominal distension, abdominal masses, etc., the diagnosis is not clear. (3) If there is a suspected terminal ileal and colonic lesion on x-ray barium enema examination, or if the nature of the lesion cannot be determined. (4) Negative x-ray barium enema examination, but with obvious intestinal symptoms or suspected malignant changes. (5) Those who have low intestinal obstruction and abdominal mass and cannot exclude colonic disease. (6) Those who present with unexplained wasting or anemia. (7) Those who need colonoscopic treatment, such as patients with colon polypectomy, hemostasis, sigmoid colon torsion or intestinal loop repositioning, etc. (8) Those who need to check the anastomosis condition after colon resection (9) Those who need regular colonoscopy follow-up after colon cancer surgery, polypectomy and inflammatory bowel disease medication (10) Those who need colonoscopy to assist in exploration and treatment during surgery for intestinal diseases (11) Those who need to be screened for colorectal diseases, such as elderly people over 65 years old or those who have a family history of gastrointestinal malignant diseases. After all, colonoscopy is also an in vivo operation, which is considered a minor surgery. For example, the presence of severe cardiopulmonary insufficiency, shock, abdominal aortic aneurysm, acute peritonitis, intestinal perforation and other people are absolute contraindications to colonoscopy. Pregnancy, frailty, advanced age, and those with severe cardiovascular disease and intolerance to the examination must be examined with caution. In addition, those with severe purulent inflammation or painful lesions in the anus and rectum, such as perianal abscess and anal fissure, who cannot tolerate the examination, must also be examined with caution. If necessary, the examination can be performed under general anesthesia; the examination is generally not recommended for women during menstruation.