Colon cancer is a common malignant tumor of the gastrointestinal tract occurring in the colon, which is usually found at the junction of rectum and sigmoid colon, with the highest incidence rate in the age group of 40-50 years old, and the ratio of men to women is 2 to 3:1. The following are the clinical manifestations of colorectal cancer: 1. Blood in stool: it is the earliest and most common manifestation of colorectal cancer. In light cases, it only shows a small amount of bleeding occasionally, and it is only after laboratory test that a small amount of bleeding is known; in heavy cases, it can show mucus-blood stool, mucus-pus-blood stool or fresh blood stool, which is often misdiagnosed as dysentery or hemorrhoid bleeding and misses the time to confirm the diagnosis. Due to the different locations of the cancer, the bleeding volume and nature vary, and long-term bleeding may produce secondary anemia. 2.Abdominal pain: Some patients have persistent vague pain with inaccurate localization as the first or prominent symptom, while some patients only have abdominal discomfort or bloating. When colorectal cancer combined with erosion, obstruction or secondary infection, due to increased peristalsis and spasm of the corresponding intestinal segment, obvious abdominal colic may appear. Some patients show typical incomplete intestinal obstructive abdominal pain, i.e. the pain is paroxysmal colic, which lasts for several minutes, with self-conscious gas running through the pain, followed by exhaust, and then the pain suddenly disappears, when such symptoms appear in the elderly, colorectal cancer should be considered first. 3. Change in bowel habits: The change in the number of bowel movements or stool characteristics, for example, the original stool was once a day, but recently for some reason it is 3 to 4 times a day, or the alternation of diarrhea and constipation, as well as the change in the shape of stool, which was soft and formed, but recently it is suddenly like water, and there seems to be blood or pus in it, remind that there may be problems in the intestinal tract, and you should go to the hospital for You should go to the hospital for a medical examination. (It should be noted that these symptoms are also common in other diseases, so a thorough physical examination should be performed if you have these symptoms). Some people also have a feeling of urgency, especially in young people. If there are no other reasons (including travel, change of living environment and taking hyoscine, etc.) and constipation and diarrhea and other intestinal disorders often occur, and regular treatment is still ineffective for more than two weeks, it should be noted that it may be an early sign of colorectal cancer. 4.Anemia: male patients, especially those who have no other causes of blood loss or intestinal parasitic disease, should think of the possibility of stomach or colon cancer if they find progressive iron deficiency anemia.