Dasatinib is used to treat a certain type of chronic myeloid leukemia (CML; a type of cancer of the white blood cells) as a first treatment and in people who can no longer benefit from other leukemia medications including imatinib (Gleevec) or in those who cannot take these medications because of side effects. Dasatinib is also used to treat a certain type of chronic CML in children. Dasatinib is also used to treat a certain type of acute lymphoblastic leukemia (ALL; a type of cancer of the white blood cells) in people who can no longer benefit from other leukemia medications or who cannot take these medications because of side effects. Dasatinib is in a class of medications called kinase inhibitors. It works by blocking the action of an abnormal protein that signals cancer cells to multiply. This helps stop the spread of cancer cells.