Chemotherapeutic drugs can kill cancer cells and damage normal tissues at the same time. The most common side effects are bone marrow hematopoietic suppression and liver and kidney function damage. 1, myelosuppression: It is the most common toxic reaction of chemotherapy drugs in clinical practice. Most chemotherapy drugs will cause growth inhibition of hematopoietic system, leukopenia, thrombocytopenia and anemia, causing fever, bleeding and anemia symptoms. Common drugs include erythromycin, cyclophosphamide, 6-mercaptopurine, pedialyte glycosides, malilan, cytarabine and mafran. Huang Wenrong, Department of Hematology, Beijing 301 Hospital 2, gastrointestinal toxicity: common manifestations are nausea, vomiting, many chemotherapy drugs can cause this reaction, such as erythromycin, vincristine, cyclophosphamide, cytarabine, methotrexate, huperzine, etc.. The next is mucositis, such as stomatitis, tongue inflammation, esophagitis, oral ulcer disease, common in the use of radiotherapy and methotrexate, cytarabine and vincristine, etc. 3, Hepatotoxicity:There are mainly 3 aspects, including hepatocellular damage necrosis, hepatic fibrosis, hepatic vein occlusion. In mild cases, the symptoms are transient increase of transaminases, alkaline phosphatase and bilirubin, while in severe cases, there may be obvious clinical symptoms. Common drugs that can cause hepatotoxicity include cytarabine, methotrexate, 6-mercaptopurine, lomustine, cytarabine, pedialyte, levomenthase, cyclophosphamide, etc. 4, nephrotoxicity: chemotherapeutic drugs on the urinary system damage includes two types: one type of renal parenchymal injury, the other type of urinary tract irritation reaction. Clinical manifestations can be uric acid nephropathy, tumor lysis syndrome, renal insufficiency, hemorrhagic cystitis, hematuria, proteinuria, electrolyte disorders, etc. Commonly seen in high dose cyclophosphamide, isocyclophosphamide, etc. 5, cardiotoxicity:Cardiotoxicity of chemotherapeutic drugs is divided into 3 types according to their appearance time. Acute toxicity mostly occurs during the course of drug administration, manifested as non-specific electrocardiographic changes; subacute toxicity often occurs within 4 weeks after the first or second course of drug administration; chronic toxicity is the most important toxic effect, mainly manifested as cardiomyopathy, common with anthracycline antibiotics. The most important toxic effect in chronic toxicity is cardiomyopathy, which is common with anthracycline antibiotics. It is manifested as arrhythmia, conduction block, tachycardia, cardiomyopathy and even heart failure after drug administration. Mostly seen in the use of adriamycin, epi-amycin, erythromycin, trichothecene, etc. 6, neurological toxicity: manifested as numbness of fingers and toes, muscle pain, foot drop, wrist drop, hoarseness, eyelid drop, facial nerve paralysis, loss of Achilles reflex, etc. Common drugs are vincristine. Large doses of cytarabine and intrathecal methotrexate can cause brain symptoms, including headache, drowsiness, apathy, inattention and convulsions. 7, pulmonary toxicity: manifested as dyspnea, dry cough, fever, a few have chest pain, the main lesions are pulmonary fibrosis, pulmonary infiltration, etc.. Commonly used in the use of nitrogen mustard phenylbutyrate, nitrogen mustard, Marilan and other drugs. 8, hypersensitivity reactions: the main manifestation is the sudden occurrence of toxic reactions, often more serious, reactions such as hypotension or hypertension, chills, fever, rash, angioedema, laryngospasm, shortness of breath, etc.. The most important drugs that cause hypersensitivity reactions are levomenthase, pedialyte glycosides and ATG, which are commonly used in transplantation. 9, drug extravasation and secondary phlebitis: erythromycin, vincristine, cytarabine and other drugs have strong irritation, such as injection into the blood vessels, will cause local pain, phlebitis, blistering, tissue necrosis, etc.