First of all, let’s talk about the principles of diet for cancer patients. Appropriate nutritional therapy can not only improve the nutritional status of patients, make their immunity and anticancer ability strengthened, but also improve the tolerance of tumor patients to surgical treatments, reduce or avoid surgical complications, and make postoperative wounds heal as scheduled; improve the tolerance of tumor patients to radiotherapy or chemotherapy to alleviate their side effects. The main principles of diet therapy for cancer patients are: for patients with existing malnutrition manifestations, auxiliary nutritional therapy should be given, such as appropriate enhancement of dietary nutrition, supplemented by parenteral nutrition when necessary. The body weight of cancer patients can be used as an indicator of the adequacy of protein and calorie intake. The weight standard can be calculated according to age and height, or compared with the patients before and after treatment. Cancer patients need about 20% more protein and calories in addition to the normal requirements of normal people. Eat more foods rich in vitamins A, E and B vitamins. Carrot and vitamin E have the effect of preventing and treating cancer. Although B vitamins do not directly fight cancer, they can regulate many physiological functions of the human body and are necessary for human metabolism. According to the nutritional science of traditional Chinese medicine, the dietary therapy for cancer patients should be based on the four qi and five flavors of the food itself, combined with the patient’s condition, and the implementation of “dialectical food”. Cancer patients mostly suffer from deficiency of positive qi, plus surgery, radiotherapy, chemotherapy, etc. often damage positive qi, so the role of positive food in cancer diet is particularly important. Eat a diet rich in fiber and stick to a low-fat diet. Cancer patients should avoid eating moldy food, burnt meat, old fried food, salt pickled food, long storage of corrupt vegetables. Secondly, we should talk about the dietary taboos of cancer patients. Chinese medicine emphasizes the “dietary taboos”, which refers to the patients’ abstinence from certain diets. TCM attaches great importance to dietary taboos. The earliest medical book “Nei Jing” has already recorded the food “five flavors are forbidden.” The Golden Chamber says, “The flavor of food is harmful to the body,” and this “harmful to the body” means that improper diet will be detrimental to the body. Avoiding this kind of disadvantage is “avoiding food”. Modern medicine also recognizes that the occurrence of colorectal cancer is related to the excessive consumption of red meat. Avoiding food is an important part of disease care. For cancer patients, it is especially important to avoid food throughout the whole process of disease treatment and rehabilitation. First of all, we should pay attention to the relationship between food avoidance and the disease contained in Chinese medicine. It is necessary to consider the symptoms of the disease, such as cold, heat, deficiency and actuality, combined with the nature and flavor of the food in a comprehensive manner. Any diet that is unfavorable to the disease should be avoided. For example, skin cancer ulcer is forbidden to eat meat and fishy food, lung cancer is forbidden to eat spicy food, edema is forbidden to eat salt, jaundice is forbidden to eat fat, warm and hot disease is forbidden to eat spicy and hot food; cold disease is forbidden to eat fruits and vegetables cold. (Observe the nail prints can know the dietary taboos, nail prints more than 7-8 people are easy to fire, cautious food or not eat spicy hot food; nail prints 4 or less, cautious food or not eat cold products). Patients with tumors of oral cavity, pharynx, esophagus, stomach, intestines, liver, pancreas and other digestive organs should eat less or do not eat meat, fat, thick and deep-fried food. Radiotherapy is regarded as the evil of heat and toxicity in Chinese medicine, which is most likely to consume fluid and symptoms of gastric yin insufficiency: such as dry mouth and little food, glossy red tongue with no moss, and nausea from time to time. At this time should be avoided hot, spicy, dry and hurt yin drugs and food. Can eat more vegetables, fruits and other cold food; but not too much, otherwise it will affect the patient’s gastrointestinal function. Secondly, we should pay attention to avoiding food when taking medicine. For example, the patient is taking the spleen and stomach, warming the Chinese medicine, and dietary intake of cold slippery food, obviously this is not appropriate. On the folk said “hairy things” taboo issue is necessary to mention here. The so-called “hairy food” refers to certain foods that can aggravate or induce disease aggravation. Modern medicine believes that some of the disease aggravation caused by hairy food is related to allergic diseases, such as asthma, hives, etc. Some of them are related to external diseases, such as sores and ulcers, rubella, rashes and poisons, etc. The hairy food is mostly found in aquatic products. Fertilizer refers to aquatic products in the scallop, carp, eel, clams, crabs, shrimp, sea cucumbers; animal meat lamb, dog meat, donkey meat, horse meat; vegetables in the leek, celery, parsley, fennel and so on. These foods are mostly sweet, warm, fragrant and dry, after eating will help heat and fire. Certain animal traditional Chinese medicines contain heterogeneous proteins, which can also cause allergies and should be paid attention to when applying. In a word, tumor patients’ dietary contraindications should be different from disease to disease, from person to person, and from treatment method to treatment method. It cannot be generalized mechanically to stipulate what can and cannot be eaten. Cancer patients should pay attention to the dietary aspects to follow the traditional scientific basis of the taboo habits, and for the kind of excessively demanding taboos, and even the practice of the mystery does not have to listen to the words. Because this also “taboo”, that also “taboo”, and even eggs, tofu, vegetables do not dare to eat, taboo to the end, the patient’s nutritional status will deteriorate, is not conducive to treatment and recovery. Modern medicine also has a “taboo”, Western medicine is generally not explicitly advocate taboo, but also emphasize the impact of diet on disease, many of which coincide with the Chinese medicine. For example, the food contaminated by Aspergillus flavus, can not eat; esophageal cancer and eating too fast, too hot; burnt food easy to make protein denaturation, pyrolysis and heat polymerization is easy to produce polycyclic aromatic hydrocarbons compounds, harmful to the human body, do not advocate eating. Smoked fish, smoked meat also do not advocate eating more. Alcohol can reduce the body’s detoxification function and bioconversion function, so that the immune system is low; alcohol at the same time in the body to increase the activity of carcinogens, and has cytotoxicity, so do not advocate drinking alcohol. During the period of taking medicine, there are some foods that can not be eaten, such as taking vitamin C during the period should not eat shrimp, because vitamin C can make the pentavalent arsenic in shrimp reduce to arsenic trioxide, which is the arsenic that is often said in the ancient novels, and it has a great deal of toxicity to the human body, and so on. Dietary contraindications should be different for different symptoms and treatments related to tumor patients. For example, liver cancer patients with portal hypertension should eat less and more meals, eat soft and easy-to-digest products, avoid overfilling, fried, hard and hard products that are difficult to be digested; Fluorouracil can sometimes cause severe diarrhea, so spinach, honey, pears and other cold and slippery products should be avoided when using the medicine. In the course of chemotherapy, it is advisable to eat light, low-fat food, be careful to eat high-fat, fried, cold, high sugar products. Contraindication as an important content of dietetics, is a common concern of doctors and patients, the correct play an important role in diet, to avoid the shortcomings, will be conducive to the treatment of disease, accelerate the recovery of patients, thereby improving the quality of survival of patients.