Excessive intake of carcinogens is a direct cause of cancer. The strong carcinogen that makes people fearful is called nitrosamines. However, many people do not know that the predecessors of nitrosamines are nitrates and nitrites. These two substances are found in many common foods, so cancer-causing “bombs” are hidden around us. The cancer crisis is always hidden in our daily meals. Many plants contain nitrites, and vegetables, especially leftover vegetables, contain a lot of nitrites. Many people like to eat pickled fish, but in fact, pickled vegetables contain a lot of nitrite compounds. The same goes for other pickled vegetables. After these chemicals enter the body, under the right conditions, they can be synthesized in the gastrointestinal tract nitrosamines. When they accumulate to a certain level, they can cause cancer. Aflatoxin is also a “famous” among carcinogens. Moldy peanuts and corn contain large amounts of aflatoxin. Aflatoxin can cause liver cancer and other digestive tract tumors. The most obvious example is that in some areas, residents of corn as a staple food, corn mold is eaten, so the aflatoxin contamination is serious, the incidence of liver cancer in residents is correspondingly high. In some areas where smoked food is often consumed, the incidence of stomach cancer is high. Because smoked food contains benzene and some other carcinogens, they are in the process of smoking, contaminated by the benzene in the smoke and the formation of protein elements and amino acids in the food by heat decomposition. In a sense, cancer is also a disease of affluence. Life is better, and there are more big fish and meat on the table. However, many people do not know that high-fat food is also a major culprit of cancer. High-fat and low-fiber food can easily cause colon cancer because high-fat food will stimulate the secretion of bile acid. After the action of bacteria in the intestine, high-fat food will slowly turn into certain carcinogens. Together with low fiber, intestinal peristalsis will slow down. Thus, the poor digestion and the longer the stool stays in the intestine, the longer the absorption of carcinogens will be. Therefore, it is important to eat more fruits and vegetables in general. In addition, some small preferences may also cause cancer. For example, some people like to drink hot thin rice and some people like to chew hard fava beans. Both hot and hard foods can cause long-term chronic irritation to the esophagus. These irritations allow one’s epithelial cells to possibly undergo atypical proliferation, which can then transform into cancer, and this is how many oral mucosal cancers are formed.