A drug used with other drugs to treat acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), and chronic myeloid leukemia (CML). It is also used to prevent and treat a type of leukemia that has spread to the meninges (three thin layers of tissue that cover and protect the brain and spinal cord). It is also being studied in the treatment of other types of cancer. Cytarabine blocks cells from making DNA and may kill cancer cells. It is a type of antimetabolite. Also called ARA-C.