Chemotherapy is the method of killing tumor cells with drugs, which is an important treatment for tumors today. However, most chemotherapeutic drugs are cytotoxic drugs which are “good and bad”, and kill many normal cells while attacking tumors, thus causing a series of adverse reactions, such as nausea, vomiting, diarrhea, decreased blood count, damage to liver and kidney function, and hair loss. These toxic side effects seriously affect the quality of life of patients, and even make people give up treatment for fear. What are the common adverse reactions of chemotherapy drugs and their causes? 1, gastrointestinal reactions: the most common ones are anorexia, nausea, vomiting, diarrhea and constipation. This is often because chemotherapy drugs stimulate the vomiting center in the brain or damage the mucosa of the gastrointestinal tract, causing its edema and can not absorb food nutrients. Therefore, when vomiting is heavy, it is advisable to start with fresh rice soup, lotus root juice and other stomach-friendly foods, so that the gastrointestinal tract can fully recuperate while absorbing nutrients; then, with the recovery of appetite, gradually transition to egg custard, minced meat porridge, hanging noodle soup and other semi-liquid foods, and then gradually resume a normal diet. If the diarrhea lasts for a long time, you can also consume some yogurt, yam and other foods under the guidance of a doctor, which may help stabilize the distribution of flora and restore intestinal function. On the contrary, if the constipation lasts longer, you should eat more fiber-rich foods and fresh fruits, such as celery, banana, honey, etc., to help defecate. 2.Lower blood count: including the reduction of white blood cells, red blood cells and platelets. This is caused by chemotherapy drugs that damage the hematopoietic stem cells in the bone marrow and prevent them from proliferating into mature blood cells. In addition to the use of hematopoietic drugs, patients can also eat more red dates, peanuts, pig liver, spinach, blood tofu and other protein-rich foods, or under the guidance of the doctor, eat some Agaricus and American ginseng. Special attention should be paid to the fact that the immune function of patients is often at a low point at this time, so special attention should be paid to not getting cold and adequate rest. 3, heart, liver, kidney function damage and oral mucosa, skin ulcers: this often need to be treated under the guidance of doctors, rather than just rely on “dietary supplements” that can be recovered. 4, hair loss: seemingly “insignificant”, but also to many patients (especially women) brought untold suffering. In addition to the medicine, you can eat some walnuts, honey and black sesame paste, can help grow new hair.