Cyclophosphamide side effects mainly include myelopoietic inhibition, gastrointestinal reactions, urinary system damage, liver damage, cardiovascular system and respiratory system damage and other damage, etc. It is recommended to use the drug reasonably under the guidance of the doctor. 1. Bone marrow hematopoietic inhibition: as the main side effect, bone marrow hematopoietic inhibition is mainly manifested in the decline of white blood cells and platelets and anemia, the decline of white blood cells has the risk of secondary infection, the decline of platelets has the risk of more than one hemorrhage, and the anemia may lead to generalized fatigue and pallor. 2. Gastrointestinal reaction: it can cause gastric mucous membrane damage, nausea, vomiting, anorexia and other symptoms, serious may lead to gastric ulcer, causing gastrointestinal bleeding. 3. Urinary system damage: Cyclophosphamide is excreted through the kidneys, which may cause hemorrhagic cystitis and other conditions. 4. Liver damage: It may cause liver dysfunction, causing the rise of liver function indexes, such as bilirubin, alanine aminotransferase, glutamic oxalate aminotransferase, alkaline sodium phosphate and so on. 5. Cardiovascular system and respiratory system damage: cardiovascular system is mainly arrhythmia, decreased ejection fraction of the left heart, and respiratory system damage is mainly limited pneumonia and pulmonary fibrosis. 6. Other damages: the main manifestations are alopecia, palms, nails and feet pigmentation. It is contraindicated in patients with known hypersensitivity to cyclophosphamide and its metabolites, severe bone marrow impairment (myelosuppression, especially in patients who have been treated with cytotoxic drugs and/or radiation therapy), inflammation of the bladder (cystitis), urinary tract obstruction, acute infections. The use of drugs should be carried out under the supervision of a doctor and adjust the dosage under the supervision of a doctor.