Before using cyclophosphamide, tell your doctor or pharmacist if you are allergic to it; or to other chemotherapy drugs (e.g., busulfan, chlorambucil); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details. This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: decreased bone marrow function (e.g., anemia, leukopenia, thrombocytopenia). Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver disease, kidney disease, surgery to remove your adrenal glands. Cyclophosphamide can make you more likely to get infections or may worsen any current infections. Therefore, wash your hands well to prevent the spread of infection. Avoid contact with people who have infections that may spread to others (such as chickenpox, measles, flu). Consult your doctor if you have been exposed to an infection or for more details.