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 and reproduction of cancer cells, ultimately leading to their destruction. Cyclophosphamide is also used to manage certain autoimmune diseases, such as lupus and rheumatoid arthritis. This drug is administered either orally or intravenously and is often part of a combination therapy. While effective, cyclophosphamide can cause side effects, including nausea, hair loss, and an increased risk of infection due to its impact on the immune system. Regular monitoring by healthcare professionals is essential during treatment.