Imatinib is a medication primarily used to treat certain types of cancer, particularly chronic myeloid leukemia (CML) and some gastrointestinal stromal tumors (GISTs). It works by inhibiting specific proteins that promote the growth of cancer cells, effectively slowing down or stopping their proliferation. Approved by the U.S. Food and Drug Administration (FDA) in 2001, imatinib is taken orally and has significantly improved the prognosis for patients with these conditions. It is often well-tolerated, but some patients may experience side effects such as nausea, fatigue, or swelling. Regular monitoring by healthcare professionals is essential during treatment.