The side effects of chemotherapy for gastric cancer are relatively large. If the patient has nausea and vomiting on that day, the doctor will originally use antiemetic drugs, triple antiemetic, and supplement sufficient nutrition at the same time. On the day of chemotherapy, patients can eat, mainly high-protein, easily digestible food, less greasy and fatty food, and also some fruits. If patients can’t eat, they can go to the nutrition department for consultation and eat some protein powder, and at the same time, they can also do extra-gastrointestinal nutrition therapy. For gastric cancer, if there is not much reaction to chemotherapy, it is recommended to have small amount and many meals. Even if the patient has some reactions, such as vomiting, you can divide three meals into six and eat again after vomiting, which is also the principle of small amount and multiple meals. Food that people can eat is the best nutritional supplement, which is more effective and economical than intravenous medication and in line with the physical condition. Lung cancer, stomach cancer, these tumors can be eaten on the day of chemotherapy. Of course, some highly emetogenic drugs have delayed reactions after hitting, and these are not important. The key is how health care professionals can reduce the toxic side effects of chemotherapy, so that patients’ appetite can be improved and nutrition can be balanced, and the focus should be on supporting treatment.