Patients who have undergone chemotherapy know that it is often accompanied by nausea, vomiting, and even bloating and diarrhea, which severely affects the diet and lasts for as little as 2-3 days, or as long as 4-7 days, or even longer. So many people are concerned about how to nutrition during these days when it is most difficult? In fact, the nutrition during chemotherapy, we should focus on the reaction period outside, nutritional enhancement method is placed after the reaction period. During the reaction period, due to the edema of the intestinal mucosa, intestinal peristalsis is abnormal, even if you barely eat as well as barely supplemental nutrients, it is also very difficult to be absorbed, extraordinarily increase the degree of gastrointestinal reaction. Nutritional principles during chemotherapy include the following points, please take the right place: 1, there was no weight loss and malnutrition patients: digestive reaction in 2-3 days after the gradual recovery, can not do nutritional support, pay attention to water supplementation can be. Digestive tract reaction in 4-7 days, try to supplement water and electrolytes by mouth. If vomiting or diarrhea is severe, please find a doctor to give glucose saline and electrolytes intravenously, or oral nutritional supplementation, or intravenous nutrition. If feeding is poor for more than 7 days, oral nutritional supplementation with combined intravenous nutritional support is required; seek assistance from a clinician or dietitian. In the above three cases, during the reaction period, there will be mild weight loss. Once the appetite is restored, it is important to increase the amount of food and drink appropriately (beyond the usual level), and combine with oral nutritional preparation supplementation to gain back the lost weight and enter the next cycle of chemotherapy. 2.Patients who already have weight loss and malnutrition It is recommended to optimize the diet and increase the energy and protein intake throughout the chemotherapy period, while supplementing with oral nutritional preparations routinely.