Rectal cancer and colon cancer are collectively known as colorectal cancer, which is one of the most common malignant tumors. According to relevant information, the incidence of colorectal cancer occupies the 4th place among all malignant tumors, and there is a trend of gradual increase. The age of onset is mostly above 40 years old, and there are more men than women. The occurrence of colorectal cancer is related to chronic inflammation, colorectal polyps, adenoma and certain genetic factors. In addition, the increase of unsaturated polycyclic hydrocarbons caused by high-protein and high-fat diet increases the risk of carcinogenesis, coupled with the decrease of fiber food intake, excessive fecal storage and the accumulation of carcinogenic substances, which easily leads to colorectal cancer. Abdominal obesity and constipation are also high-risk factors of colorectal cancer. Bloody stool or mucopurulent stool, change of stool shape or habit, abdominal pain, abdominal mass, etc. are common in clinical practice. Depending on the site of occurrence, the clinical manifestations are often specific to each stage. Most of the patients with colorectal cancer can get better results due to timely treatment. Therefore, we should pay attention to the following symptoms: 1. Blood in stool. It is one of the early symptoms of all colorectal cancers, but the time and nature of bleeding of tumors in different parts are different. For rectal cancer, the amount is very small in the early stage, mostly with fresh blood marks on the side of the stool. A few patients can discharge a large amount of fresh blood after stool. In contrast, the bleeding from tumors in all segments of the colon may darken due to the longer stay in the intestine, and the color of the blood in stool may become darker to the point of discharging violet or black-purple stool, and the appearance of blood in stool is relatively late, which is not necessarily the first symptom of the patient. Often, due to the small amount of blood or a long residence time, the naked eye can not be detected, only positive stool occult blood test. 2. Change in stool habit. Including the change of stool time, frequency, and alternating constipation and diarrhea. Sometimes there is only some mucus and blood in the stool, and there is a feeling of incomplete defecation. 3. Painful bowel movement. About 50% of rectal cancer patients have pain during defecation, the degree of which may be mild or severe. 4.Abdominal pain. Some patients have vague abdominal pain as the prominent symptom, while others have paroxysmal colic with abdominal distension. 5.Weakness, anemia and abdominal mass. In the right hemicolectomy, due to the growth pattern of the mass and failure to detect it in time, the mass can often be palpated in the abdominal wall and systemic manifestations such as anemia are already present. Early diagnosis has a greater impact on prognosis. Regular general physical examination, necessary examination, can be detected at an early stage, and abnormalities such as blood in stool, stool secretion, abdominal distension and discomfort or unexplained wasting should be promptly performed colonoscopy, barium enema and other related examinations. Warm tips: maintain a balanced diet, smooth bowel movements, good living and eating habits; regular routine medical checkups; go to the hospital for necessary examinations or consultations in a timely manner in case of blood in the stool, urination, abdominal distension or unexplained weight loss, anemia and other abnormalities, instead of just buying some medicine to deal with the matter. Colonoscopy, barium enema and other related examinations are common examinations that can be fully tolerated and should not delay the diagnosis due to excessive worries. Screening for colorectal cancer includes fecal occult blood test, colonoscopy or barium enema for people over 50 years old to start, etc.