At present, there is no special method for early detection of colorectal cancer, but if we can be alert, pay attention to the “ten warning signs” of early colorectal cancer and conduct “one finger and three examinations” in time, we can detect colorectal cancer earlier. More than 90% of early colorectal cancer can be completely cured. The “ten warning signs” are: (1) Sudden weight loss. (2) Anemia of unknown cause. (3) Abdominal distension, abdominal pain, indigestion and loss of appetite. (4) Lumps in the abdomen. (5) Blood in the stool or black stool. (6) Pus and blood in stool or mucus and blood in stool. (7) Change in stool habit, increased frequency or diarrhea. (8) Alternating diarrhea and constipation. (9) Change in stool shape, thinning, flattening or grooving. (10) Finding of multiple occurring polyps, or papillary adenomas. ”Since more than 50% of colorectal cancers occur in the rectum and 70% of rectal cancers are low rectal cancers, the diagnosis can often be confirmed by simple rectal finger examination. The doctor’s index finger is inserted into the anorectum and can generally touch the area of about 7~8 cm. The sensation of the finger is sensitive and can obtain more accurate information than endoscopy and X-ray on the size, hardness, mobility, ulceration, bleeding, spread and metastasis of the lesion. However, some people are afraid that the doctor may use the X-ray to detect rectal cancer. However, some people are afraid of doctors touching the rectum with their fingers, and they would rather take drugs indiscriminately than go for serious examination when they have symptoms, which delays the early detection of rectal cancer. Therefore, we should not “touch the tiger’s buttocks” and should cooperate with the doctor’s examination. Even if you feel no symptoms, you should let the doctor feel the anorectum during physical examination or census, as many early rectal cancers are found through physical examination or census. (2) Endoscopy Endoscopes include anoscope, sigmoidoscope, fiberoptic colonoscope, etc. Anoscopy can see 10 cm, sigmoidoscopy can see 25 cm, and fiberscope can see the general shape of the whole colon and take biopsy for histocytological examination, so it is a powerful means to detect early colorectal cancer and other diseases. Endoscopy is generally painless, and as long as it is performed correctly, nothing can go wrong. (3) X-ray examination, including barium enema, double contrast imaging, abdominal plain film and other X-ray examinations, is also valuable for early detection of colorectal cancer. (4) Stool occult blood test is a simple method to detect blood in stool that is invisible to the naked eye through laboratory tests. If bleeding is found (positive), a full examination can be performed. It is also useful for detecting early colorectal cancer. If suspicious lumps, ulcers or bleeding spots are found in these tests, and then a few small biopsies are taken from these areas for histocytological pathological examination, it can determine whether it is early colorectal cancer.