According to clinical statistics, patients’ physical fitness is directly related to their nutritional intake. If patients’ nutritional intake is sufficient and their nutritional level is in a better state, the efficacy of chemotherapy will be correspondingly good; on the contrary, if the nutritional intake is not much and the nutritional level of the patients’ body is poor, the efficacy of chemotherapy is poor, and the adverse reactions will be greater. Therefore, the diet of cancer patients in the pre-chemotherapy period plays an important role in the effect of treatment. Cancer is a kind of consumptive disease, even though patients are less active, their body’s metabolism is running constantly, which will easily lead to a large amount of fat and protein loss in the body. In order to ensure a better physical condition during chemotherapy, patients are generally required to enhance their physical condition and increase nutrition before treatment, and a low-fat, high-carbohydrate, high-fiber diet is generally required the day before chemotherapy. During early chemotherapy, due to the influence of toxic side effects of chemotherapeutic drugs, patients will experience different degrees of loss of appetite, nausea and vomiting and other adverse reactions; coupled with the family’s initial failure to correctly perceive the knowledge of nutrition, blindly believe that more meat is nutritionally adequate, so that the original nutritionally impaired patients even more loss of appetite. During this period, patients and their families should be given reasonable health knowledge education, psychological guidance, with scientific diet: diet should be light, nutrition-based, eat high protein, high calorie food, cooking methods can choose to steam, boiled, avoid greasy food, spicy, fried food, do not eat moldy, barbecue, smoky food, eat more soy products, dairy products, fish, meat to replenish the necessary protein, can more Eat more fiber foods such as bananas, squash and other fresh fruits and vegetables, drink more warm water, to ensure smooth bowel movements; in addition, more variations in the types of food, from the color, aroma and taste to improve the patient’s appetite. Chemotherapy easily leads to low white blood cells, platelets, red blood cells, etc. In addition to a diet rich in foods containing polymer polysaccharides (e.g. shiitake mushrooms, enoki mushrooms, enoki mushrooms, black fungus, etc.), vitamins (e.g. jujubes), and blood (e.g. jujubes, raw peanuts, chicken, etc.), patients also need to pay attention to warmth, and avoid going to crowded places to avoid catching colds, fevers, and infections because of their low immune system.