Chemotherapy is still relatively harmful to the body, so it is usually necessary to assess the patient’s physical condition and whether he or she can tolerate chemotherapy before chemotherapy. Chemotherapy drugs are cytotoxic drugs, which have a relatively large impact on organs, such as the heart, liver and kidney function. Therefore, for patients with chronic liver or kidney disease or poor cardiac function, the physician must evaluate the patient’s ability to tolerate chemotherapy before chemotherapy is administered. Cytotoxic drugs can also have a suppressive effect on the bone marrow, which is manifested by a decrease in peripheral blood leukocytes and platelets, and can even cause anemia. Leukopenia can lead to immune deficiency, which can lead to serious infections or even fatalities, and thrombocytopenia can cause bleeding, which are serious complications of chemotherapy. The effect of chemotherapy drugs on the gastrointestinal tract is relatively large, and nausea and vomiting usually occur in chemotherapy. With the increasing maturity of chemotherapy technology and the improvement of chemotherapy drugs through several generations, the impact on organ function has been gradually reduced. Moreover, there are various supportive drugs in chemotherapy, such as anti-emetic drugs or drugs to prevent heart, liver and kidney toxicity, which can ensure that patients can pass through the chemotherapy period in a safer way. Therefore, although chemotherapy has an impact on the body, it is still an effective method for treating malignant tumors.