Gastrointestinal tumors, mainly gastric cancer and colorectal cancer, are highly prevalent in China and seriously endanger people’s health and even lives. Although the current treatment means (surgery, chemotherapy, radiotherapy, immunotherapy, etc.) and level are getting higher and higher, and the cure rate is increasing, still a large proportion of patients cannot be cured, especially those who are found to be in the middle or late stage. The earlier cancer patients are treated, the better the effect will be. So, how can we achieve early detection and early treatment? Causes of stomach cancer and colorectal cancer 1. Genetic factors. The development of tumor has the tendency of family gathering, that is, genetic inheritance tendency. Unlike some genetic diseases, the risk of children suffering from the disease is higher than that of ordinary people. Gastric cancer has an obvious tendency of family clustering, and the family incidence rate is 2-3 times higher than that of the general population. For example, Napoleon’s grandfather, father and three sisters all died of stomach cancer, and the whole family, including himself, had 7 people suffering from stomach cancer. This means that genetic factors, congenital, we cannot change our origin. Then, if a blood relative in the family has stomach or intestinal cancer, be careful yourself, the closer the relative is, the more attention you should pay. Once you have digestive tract discomfort, be alert and seek medical attention in time. If necessary, gastroscopy and colonoscopy should be performed, which is the most crucial part of early detection. 2. Environmental factors. At present, the environment we live in is getting worse and worse, with air pollution, food and water pollution, extensive use of pesticides and fertilizers, and abuse of hormones and antibiotics, which directly lead to the high incidence of various cancers. We now have more and more cancer patients around. High risk factors of gastric cancer 1.High salt diet: High concentration of salt can damage gastric mucosa, leading to atrophy and shedding of gastric wall cells, increasing susceptibility to carcinogens; in addition, high salt diet may increase the risk of Helicobacter pylori infection, which is highly related to the development of gastric cancer. 2.N-nitroso compounds: They are widely found in nature, and diet and drinking water are the main exposure pathways of N-nitroso compounds to humans. Many meat products currently contain nitrite additives. 3.Smoked, barbecued and fried foods: Smoked, barbecued and fried foods are easy to form polycyclic aromatic hydrocarbons such as benzo(a)pyrene during processing, and BaP is an indirect carcinogen with strong carcinogenic effect. There are many studies on the relationship between smoked, barbecued and fried foods and gastric cancer, and most of them show that smoked, barbecued and fried foods can increase the risk of gastric cancer. 4.Moldy food: The incidence of stomach cancer is decreasing globally, especially in western countries, which is related to the decrease of the probability of moldy food due to the popularity of refrigerators. Moldy food contains carcinogens such as Aspergillus flavus and Aspergillus oryzae, and regions where moldy food is often consumed often have a high incidence of stomach cancer. High incidence of gastric cancer in the area of Hebei Zanhuang County cornmeal detected Aspergillus flavus B2 and Aspergillus heterocystis. 5, Helicobacter pylori infection: H. pylori infection is an important risk factor in the development of gastric cancer. If there is an infection, eradicate it as much as possible. However, it is easy to be re-infected and try not to share utensils. Protective diet for gastric cancer: fresh vegetables and fruits, milk and soy products. High risk factors for colorectal cancer 1. high-fat and high-protein diet; 2. vegetables, fruits, cereals and fiber: most published studies show that a high intake of vegetables and fruits is associated with a low risk of colon cancer, or that vegetables and fruits play a protective agent role in the development of colon cancer; 3. trace elements and vitamins: calcium and selenium are the 2 more studied trace elements in colorectal cancer. Calcium ion can combine with lipids to form insoluble calcium soap, inhibit fatty acids and bile acids, and play a protective role for intestinal epithelium. Selenium can alter carcinogen metabolism and inhibit cell proliferation. A recent study suggests that high magnesium intake may reduce the risk of colon cancer in women. Women with high magnesium intake have a 23% lower rate of colon cancer than women with low magnesium intake. Vitamins A, C, and E may normalize the hyperproliferation of colonic epithelium in adenoma patients. In addition, obesity, chronic constipation, chronic colitis, and lack of exercise are all associated with the development of colon cancer. Therefore, in terms of environmental factors, especially diet and lifestyle, we can have a great possibility to avoid the occurrence of tumor. Cultivating good lifestyle habits, improving diet structure and exercising can reduce the risk of developing GI tumors. Summary: For those who have family history and previous history of GI diseases, such as colorectal polypectomy, partial gastrectomy for gastric ulcer, chronic gastric ulcer, Barret’s esophagitis, they should have regular fecal occult blood and gastroenteroscopy, if nothing is found in the first examination, they can be examined every two to three years in the future. It takes ten to twenty years for bowel cancer to turn from a normal tissue into a polyp and then into cancer. If a polyp is found and cut out, cancer will not occur. Another point is that for ordinary people without family history, if they have digestive tract discomfort, it is better to seek medical consultation in time. Nowadays, there are more and more disseminated digestive tract tumors. In addition, regular health checkups can detect tumors at an early stage. In general, digestive tract tumors are relatively mild in nature, and most of them can be cured in the early and middle stages.