With the increasing incidence of cancer, surgery, radiotherapy, chemotherapy and biologic therapy are still the four main treatment methods, among which radiotherapy is more commonly used, with about 70% of tumor patients receiving radiotherapy at some point in their disease. Usually, patients are admitted to the hospital and give themselves to the medical staff, putting all their hopes on the diagnosis and treatment, but it is also very important for tumor patients to have a reasonable diet during radiotherapy. The following is an introduction of the issues that should be noted in the diet of tumor patients during radiotherapy. I. What foods should be eaten during radiotherapy. After receiving radiotherapy, patients often have dry mouth and lips, red tongue with less coating, weakened sense of taste and smell, low appetite and other phenomena of fluid depletion. At this time, the patient’s diet should be highly nutritious, digestible and nourishing food, such as lotus root, water chestnut, pear juice, radish juice, mung bean soup, winter melon soup, rutabaga soup, watermelon, pumpkin, loofah, jellyfish, loquat, kelp, rhizome, etc. Eat more fish, meat, milk, honey, fresh vegetables, fruits, etc. Due to the different dietary choices of radiotherapy sites, there are also differences: 1. 1.When head tumor radiotherapy is given, take more nourishing and brain-healthy products, such as walnut, peanut, green tea, coffee, mulberry, black sesame, pomegranate, mango, ginseng fruit, pineapple honey, red date, kelp, sour date, pig brain, etc. 2.When taking radiotherapy for neck tumor, take more products that nourish yin and produce fluid, clear heat and lower fire, such as pear, orange, apple, watermelon, rhizome, lotus root, grapefruit, lemon, bitter melon, honey, green tea, wild rice, cabbage, carp, jellyfish, tamari, etc. 3.When taking radiotherapy for chest tumor, take more products that nourish Yin and moisten lung, stop cough and resolve phlegm, such as winter melon, loofah, orange, lotus root, Chinese yam, carrot, loquat fruit, apricot, etc. 4.For abdominal tumor radiotherapy, take more products that strengthen the spleen and stomach, nourish and replenish qi, such as citron, prune, hawthorn, chicken gizzard, goose blood, coic rice porridge, fresh ginger, etc. 5.When taking radiotherapy for genitourinary tumor, take more products to nourish kidney and liver and clear heat, such as wolfberry, fig, watermelon, bitter melon, sunflower seed, milk, pepper, fennel, coriander, etc. Should cancer patients avoid eating” is an issue of great concern to patients and their families. It is also a unique concept in China, which pays attention to the relationship between diet and disease, that is, “the taste of food is suitable for the disease and harmful to the body”, and tumor patients are no exception. The spicy and aromatic food such as pepper, onion, garlic, leek, eel, sheep, chicken, etc. should be avoided. The key is to “eat less, eat lightly, and not to hurt the ears”, but it is harmful to forcibly forbid.