Cyclophosphamide is a medication primarily used in chemotherapy to treat various types of cancer, including lymphoma and breast cancer. It works by interfering with the growth of cancer cells, preventing them from multiplying. This drug is also used to manage certain autoimmune diseases, such as lupus and rheumatoid arthritis. As an alkylating agent, Cyclophosphamide is converted in the body to active metabolites that damage DNA. It is usually administered intravenously or orally, and its side effects can include nausea, hair loss, and an increased risk of infection due to its impact on the immune system. Regular monitoring is essential during treatment.