Busulfan is primarily used in the treatment of chronic myelogenous leukemia (CML), a type of cancer affecting the blood and bone marrow. It works by interfering with the growth of cancer cells, ultimately leading to their destruction. Additionally, it is utilized as a conditioning agent prior to hematopoietic stem cell transplantation. In this context, it helps to suppress the patient's bone marrow, making space for the new stem cells to engraft and grow. Busulfan is administered orally or intravenously, depending on the specific treatment protocol. Its use requires careful monitoring due to potential side effects, including bone marrow suppression and pulmonary toxicity.