Colorectal cancer includes colon cancer and rectal cancer. One characteristic of the incidence in China is that most colorectal cancer patients are suffering from rectal cancer, and low rectal cancer near the anus is the most common, which leads to a lot of patients with anal excision, and they become ‘stoma’ patients after operation, which brings greater inconvenience to their life. Unlike China, there are more patients with colon cancer in western European and American countries. It is not possible to say exactly what causes the difference, but we believe that it may be related to diet and other factors. In recent years, studies and surveys have found that in some major cities in China, there has been a year-on-year increase in the number of colon cancer patients and a readjustment in the proportion of colorectal cancer. We speculate that this is likely to be related to the increasingly “westernized” dietary structure of big cities, because colon cancer is indeed more common in people who inhale a lot of saturated fat. In Europe and the United States and other countries with high incidence of colon cancer, people’s dietary fat content of about 60-120 grams per day, fat content accounted for nearly half of the total calories, and mainly saturated fats; while the low incidence of colon cancer in some countries in Asia and Africa, the amount of fat consumed by each person per day is 20-60 grams, which accounts for only one-tenth of the total calories, and unsaturated fats are predominant. Of course, further research is still underway as to whether the type of fat is absolutely related to the development of colon cancer. However, there is more agreement that saturated fats are associated with the growth of anaerobic bacteria in the intestines that produce the toxins that cause colon polyps and tumors. Whether it is colon cancer or rectal cancer, there is no medically effective preventive measures, prevention can only start from the daily diet, work and rest, adjust the mentality, etc., because more and more phenomena show that the onset of such tumors is indeed closely related to the acquired environment and the state of human existence. Lack of plant fiber is also a major cause of colorectal cancer, in addition to controlling excessive fat and protein intake, people should eat more food rich in plant fiber, such as rice, wheat, sweet potatoes, corn, barley, sorghum, oats and so on. Fresh vegetables, fruits, kelp, nori is also a good source of plant fiber. In addition, Pan Zhizhong pointed out that tobacco and alcohol are also currently recognized as important triggers of cancer.