The issue of contraindication is of great concern to people, and many patients and families often ask medical experts about this issue, in fact, this matter should be viewed from different perspectives. First of all, it can not be said that there is no reason to avoid the mouth, but it should be noted that many are special requirements under certain conditions or certain circumstances, there is no absolute contraindication, in fact, there is a problem of the amount. Secondly, the issue of taboos in ancient and modern times and in China and abroad is said to be a variety of opinions, if the collection of information strictly required, I’m afraid there is nothing to eat, not to mention what nutrition. The taboo does not exist only in China, and the reasoning behind what foods to avoid is not consistent. In some countries, the word “cancer” and “crab” are the same word, so their cancer patients do not eat crab or shrimp. Third, many statements and records are simply contradictory. For example, if you avoid something, perhaps the risk of esophageal cancer is reduced, but then some experts seriously tell you that there are studies that prove the lack of such things has increased the chance of lung cancer. Unnecessary avoidance is often counterproductive It is very necessary to pay attention to dietary contraindications in some cases, but there is no scientific basis to say that eating certain foods after cancer will cause tumor recurrence or metastasis. Sometimes we can see that some patients are very strict in avoiding food and do not eat many things, but the cancer still recurs and metastasizes. Some patients have a diversified diet, do not have a partial diet, and have a regular diet, but they live a good life. Cancer recurrence or metastasis is mainly caused by the low resistance of the body, the original cancer cells are not completely destroyed, and the result of blood or lymphatic dissemination, not caused by eating a certain food. Too much “taboo” is harmful to patients. Cancer patients should eat nutritious and easy to digest and absorb foods because of their weakness, emaciation and poor appetite. What does Chinese medicine say about diet and food taboos? Does it mean that tumor patients do not have the problem of food taboos? Can they eat anything they want? Is there no scientific basis for the saying of avoiding food? Chinese folk medicine has always paid attention to the taboo, and Chinese medicine also pays attention to the choice of food for patients in illness. According to the theory of Chinese medicine, food, like medicine, has four qualities: cold, hot, warm and cool, and five flavors: sour, bitter, sweet, pungent and salty. Therefore, cancer patients should abstain from certain foods according to different conditions, and appropriate dietary taboos are necessary. As the saying goes, “the taste of food is appropriate to the disease and harmful to the body”, those that are appropriate to the disease can be eaten, while those that are not appropriate to the disease and harmful to the body should be avoided.