Cyclophosphamide, used for malignant lymphoma, acute or chronic lymphocytic leukemia, multiple myeloma, is effective in breast cancer, ovarian cancer, lung cancer, nasopharyngeal cancer, neuroblastoma and osteosarcoma. The commonly used dosage forms of cyclophosphamide are tablets and injections, which are antitumor agents. It is forbidden to use for bone marrow suppression, infection, liver and kidney function impairment, allergy, pregnant and lactating women. Adverse reactions after taking cyclophosphamide include myelosuppression, of which leukopenia is the most common, usually 1 to 2 weeks after the drug, and most often recovered after 2 to 3 weeks. Some patients will have symptoms such as loss of appetite, nausea, vomiting, etc. Very few patients will have urinary tract and other reactions, such as oliguria, hematuria, stomatitis, menstrual disorders, azoospermia and so on. Patients are advised to take cyclophosphamide in strict compliance with the doctor’s instructions, and to go to the hospital promptly if any uncomfortable symptoms occur during the period of taking it.