In medicine, it is generally believed that the early symptoms of rectal tumor are manifested in the following aspects: 1. Abdominal discomfort Early patients with rectal tumor will start to have the symptoms of abdominal distension and dyspepsia, and then there will be the change of defecation habit, such as increased frequency of bowel movement, diarrhea or constipation, and abdominal pain before bowel movement. Later on, there will be mucus stool or mucus-pus blood stool; 2. Intestinal obstruction: Intestinal obstruction is incomplete or complete low intestinal obstruction symptoms, such as abdominal distension, abdominal pain (distension or colic), constipation or stool closure. Physical examination can see abdominal rumbling, intestinal type, localized pressure and pain, and can be heard hyperactive bowel sounds; 3. Rectal lesions Rectal palpation can be detected in the intestinal lumen cauliflower-like hard lumps, or the edge of the bulge, the center of the depressed ulcer, or intestinal luminal ring stenosis, the finger sleeve is often stained with pus and blood. Colorectal tumors located in rectum account for about half of the patients, and most of the rectal tumors can be touched during rectal palpation; 4. Intoxicating symptoms Due to blood loss and toxin absorption from tumor ulceration, patients with rectal tumors may suffer from anemia, low-grade fever, malaise, lethargy, edema and so on, in which anemia and lethargy are the main features; 5. Abdominal mass Patients with rectal tumors may also suffer from change of bowel habit, persistent abdominal discomfort, vague pain or abdominal distension, thinning of feces, or abdominal swelling, or abdominal pain. Rectal tumor patients may also have change of bowel habit, persistent abdominal discomfort, vague pain, abdominal distension, thinning of feces, or with blood and mucus, persistent positive fecal occult blood test, unexplained anemia, fatigue or weight loss, etc., and abdominal mass may be detected. Among them, the change of bowel habit in patients with rectal tumor includes constipation, diarrhea or alternating with constipation, incomplete bowel movement and difficulty in defecation. Constipation is mainly caused by acute and chronic intestinal obstruction caused by tumor. In addition, constipation is a risk factor for colorectal cancer. A large number of clinics have confirmed that there are several reasons why the incidence rate of colon cancer and rectal cancer in constipated patients is significantly higher. Long-term chronic constipation, dry feces often stagnate in the large intestine and cannot be discharged in time, which can produce adverse mechanical and physical stimulation effect on intestinal mucosa. There are some undigested fats and proteins in the intestine. Under the action of intestinal anaerobic bacteria produce amines such as nitrosamines, phenols, amines, azobenzene and other chemical carcinogens, but also produce indole, methyl indole, hydrogen sulfide and other toxic substances. Therefore, when repeated loose stools or constipation occurs, it is necessary to go to the hospital in time. It may be caused by intestinal cancer. If accompanied by symptoms such as constipation, diarrhea, unexplained weight loss, lethargy, paroxysmal vertigo and abnormal sensation of intestinal emptying, you must see an anorectal doctor.