Leukemia can occur at all ages, but different types of leukemia occur at different ages, from young children to the elderly. Leukemia can occur in newborns and the elderly, but different types of leukemia have specific age groups, for example, acute lymphoblastic leukemia is more common in children and adolescents. For example, acute lymphoblastic leukemia occurs in children as well as adolescents, while chronic lymphoblastic leukemia occurs in the elderly. Leukemia can be caused by a variety of factors, such as viral infections, X-rays, genetic factors, or secondary to other blood disorders. The mainstay of treatment is chemotherapy, which consists of two phases: induction of remission and consolidation after remission. Bone marrow transplantation is also available and is indicated for patients at intermediate to high risk. Specific drugs include cytarabine, Zoerythromycin and vincristine. Specific diagnosis and treatment should be carried out under the guidance of physicians.