Bowel cancer includes small intestine cancer and large intestine cancer, and the manifestations are different depending on the location from the anus. Clinical manifestations are mostly based on change of stool habit, blood in stool, lower abdominal pain and abdominal mass. When the above 4 obvious signals appear, one should be cautious of the occurrence of bowel cancer and should go to hospital for examination and treatment in time. Change of stool habit: It is mostly seen in colorectal cancer, which can appear as unformed stool, constipation, or alternating constipation and diarrhea, and stool can be pus stool or mucus stool. Since the small intestine cancer site is not adjacent to the anal canal, there is generally no deformation of stool. Blood in stool: 1. Small intestine cancer: because the cancer site is relatively far away from the anus, it is often intermittent discharge of tarry stool or bloody stool, or heavy bleeding, which may manifest as chronic anemia because of long-term repeated bleeding unnoticed; 2. Large intestine cancer: because the cancer site is closer to the anus, it mostly appears with fresh blood in stool. Lower abdominal pain: 1. Small intestine cancer: it can be hidden pain and distension in the lower abdomen, and when it is complicated by intestinal obstruction, it can be severe colic; 2. Colorectal cancer: it is often persistent hidden pain, with inaccurate positioning, or only abdominal discomfort and abdominal distension, and when there is intestinal obstruction, the abdominal pain is aggravated and can be paroxysmal colic. Abdominal masses: 1. Small intestine cancer: because of the long length of small intestine, the active area of the mass is larger and the location of the mass is not fixed; 2. Colorectal cancer: the mass is large and hard, and if the cancer is in the transverse colon and sigmoid colon, it can be active. If the cancer leads to intestinal perforation secondary to infection, the lump is fixed in position and may have pressure pain. In addition, patients who have long-term chronic diarrhea, posterior urgency, nausea and vomiting, or even anemia symptoms such as pallor, dizziness and weakness should be alerted to intestinal cancer, and should seek medical examination in time for clear diagnosis and early treatment to help recovery.