Bowel cancer is a relatively common disease in clinical practice, and it mostly occurs in middle-aged and elderly patients. Its clinical bleeding symptoms are mostly manifested as black blood, accompanied by mucus or purulent blood secretion. This is mainly due to the abnormal edema of the intestine caused by intestinal cancer, which stimulates the increase of intestinal secretion, which in turn leads to the increase of intestinal mucus and purulent secretion. Due to the enlargement of the cancer, it will lead to narrowing of the intestinal lumen, which in turn leads to symptoms such as intestinal adhesions, intestinal obstruction and grooves in the stool. At the same time, the patient may experience wasting, anemia and enlarged abdominal lymph nodes. Patients should be alert to the possibility of gastrointestinal malignant disease and be examined as soon as possible.