Pre-operative dietary taboos for rectal cancer: 1. fried, smoked and pickled foods: these are the key factors causing rectal cancer, so avoid excessive intake of salts in daily diet as much as possible. 2. Spicy, alcoholic, hot and other stimulating foods: It is necessary to avoid these stimulating foods because they seriously damage the intestinal mucosa. The consumption of overly stimulating food will also cause the tumor to increase intestinal peristalsis due to the breakage of intestinal mucosa, and in severe cases, it can further aggravate the symptoms of abdominal pain and constipation. High-fat and low-fiber foods: Excessive intake of fatty foods can not only burn calories, but also accelerate the growth of tumor, and the long-term gathering of stool in the intestine increases the chance of contact with harmful substances such as carcinogenic and toxins. Advocate patients to consume more vegetables and fruits and coarse fiber food, and promote the smooth defecation. Diet taboos after rectal cancer surgery: The diet after rectal cancer surgery must follow the principle of eating more easily digestible food and not eating food that produces dregs, such as nuts and vegetables that are too long to digest. In addition, strong foods should be forbidden in the diet, and spicy lovers must be forbidden to eat spicy foods early, such as strong wine, spicy and high-calorie stimulating products. In addition to these foods, rectal cancer patients should also abstain from greasy foods, barbecue and pickled foods.