The term “contraindication” in Chinese medicine refers to foods or drugs that should not be taken because of their antagonistic relationship with the body and the disease (TCM pathology), and should be considered comprehensively on the basis of the cold, heat, deficiency and actual properties of the disease, combined with the nature and taste of the food. It is generally believed that spicy and dry stimulating foods, such as chili pepper, raw onion, ginger, garlic, pepper, mustard, cinnamon, dog meat, donkey meat, leek, etc., should not be taken during radiotherapy, because such foods are most likely to hurt yin and will aggravate the disease; also avoid using warm tonic products, such as ginseng, deer antler, etc. During radiotherapy, it is advisable to eat more cool and moist vegetables, fruits and other foods, such as cucumber, winter melon, lily, spinach, shiitake mushrooms, silver fungus, lotus root, white radish, water chestnut, pear, apple, watermelon and so on. It is important to note that the intake of such foods should not be excessive, as a large amount of cold food can easily damage the stomach qi and affect the function of the spleen and stomach. Chinese medicine places great emphasis on “protecting the stomach qi”, and medication and diet must follow this principle. During radiotherapy, you can choose to drink Chinese herbal medicine as tea to benefit the qi and nourish the yin to reduce the side effects of radiotherapy. Commonly used drugs include rhizome, white foxglove, prunus, maitake, sage, dendrobium, lily, chrysanthemum, etc. Observation of nail marks can assist in judging the physical deficiency and guiding the dietary contraindications. Generally speaking, if the number of nail marks is 7 or more, the body constitution is hot and easily inflamed, so be careful or avoid eating spicy and stimulating food; if the number of nail marks is 4 or less, the body constitution is cold, so be careful or avoid eating raw and cold food. American ginseng is cooling in nature and has the effect of benefiting qi and nourishing yin, clearing heat and generating body fluid, which is more suitable for use during radiotherapy. The method is easy and effective to take western ginseng tablets. Different parts of the tumor radiotherapy process will show different complications, such as chest tumor prone to radiation pneumonia, radiation esophagitis. Radiation esophagitis is characterized by congestion and edema of the esophageal mucosa, and in severe cases, mucosal ulcers and pain behind the sternum when swallowing can occur. Radiation pneumonia can be seen as fever, wheezing, dry mouth and throat, and dry cough with little sputum. The above manifestations are mostly heat and toxicity, and the diet should be based on foods that have the effect of clearing the lungs and dissolving phlegm and toxicity. You can use a mixture of pear juice, sugar cane juice, fresh root juice, water chestnut juice, etc.; you can also often take porridge food, adding sage, lily, red beans, silver fungus, coix seeds, yam, etc. It is appropriate to add ham (Jinhua ham) for those who are weak in qi, add Chuan Bai Mu for obvious cough, add lotus seeds and sesame seeds for sleep disturbance. Commonly used classical dietary recipes, such as ice sugar lily lotus seed and silver ear soup, jujube glutinous rice and red bean porridge, Buddha’s hand porridge, etc.. In general, patients should have a light and spicy diet during radiotherapy, and they should eat less and more meals. The specific requirements of avoiding food for tumor patients vary from disease to disease, from person to person, and from treatment to treatment method. Please consult your specialist for specific dietary guidance and therapeutic methods. Do not follow harsh dietary requirements that are not scientifically based out of concern for the avoidance of food. Do not take into consideration or listen to the fictitious claims and practices of some cancer patients in terms of diet. In clinical practice, some patients are afraid to eat eggs, tofu and vegetables because of the taboo, and their nutritional status is deteriorating, which is very detrimental to treatment and recovery.