Bowel cancer is a common malignant tumor of gastrointestinal tract, which causes great impact on people. With the development of medical technology, the treatment of bowel cancer is no longer something impossible. However, the dietary contraindications of bowel cancer should never be ignored. One should reduce the intake of fats in the diet: too much fats, especially animal fats, can stimulate bile acid secretion in the small intestine. When the amount of bile acid in the intestine is too high, it will easily become carcinogenic and encourage the growth of cancer cells. Thus, high-fat diet is closely related to the occurrence of intestinal cancer. Second, to increase the intake of fiber in the diet: the main function of fiber in food is to normalize intestinal peristalsis, increase the volume of stool, and reduce the time of stool staying in the rectum. The fecal matter present in the colon makes bacteria active and may produce carcinogenic substances. When there is a lack of fiber in the diet, the feces in the colon becomes dry and hard, and this, combined with a sluggish passage and weakened abdominal wall muscles, makes the evacuation time longer, and if it takes too long, the chances of developing colon cancer are relatively higher. Studies have confirmed that fiber in food can dilute the potentially carcinogenic substances in fats and oils, and also accelerate the speed of carcinogenic substances being expelled from the body through the digestive system. According to the symptoms and performance of bowel cancer, the diet of rectal cancer can be adjusted at any time (1) Patients with bowel cancer have recurrent and persistent diarrhea, and their digestive ability is weak, so they should be given food that can be easily digested and absorbed. (2) Patients with bowel cancer mostly have blood in stool, and late stage patients often have a lot of blood in stool, so they should take less or no stimulating and spicy food. (3) Patients with prolonged diarrhea or advanced patients with long-term fever, sweating and damage to fluid, so it is appropriate to drink more water or soup, and the main food can be mainly semi-liquid Dian diet such as porridge and noodles. (4) Patients have symptoms such as loss of appetite, nausea and even vomiting, so it is appropriate to take a light diet and avoid greasy food. (5) Patients with advanced bowel cancer have prolonged diarrhea, blood in stool, fever, loss of large amount of nutrients and water, loss of body weight, weight loss and deficiency of both qi and blood, so it is appropriate to take nutritious nourishing juice diet. According to the above suggestions of dietary contraindications of bowel cancer and doctors’ treatment, rectal cancer patients can better treat the disease. The dietary taboos of bowel cancer also need to pay attention to not touching the following things (1) strong wine, spicy, hot and stimulating food. (2) High fat diet and low fiber food. (3) Do not eat fried, smoked and pickled foods.