The number of days for a course of chemotherapy is different for different types of leukemia, for example, 1 course of chemotherapy is 7 days for acute myeloid leukemia, 28 days for acute lymphoblastic leukemia, and there is no course of chemotherapy for chronic leukemia. The number of days in a course of chemotherapy for leukemia patients is related to the type of leukemia and the choice of chemotherapy regimen, and the number of days in a course of chemotherapy for different types of leukemia is also different. 1. 1 course of chemotherapy for acute myeloid leukemia is usually 7 days, and the regimen used is usually Zoerythromycin + Cytarabine, i.e., Zoerythromycin is used for 3 days, and Cytarabine is used for 7 days, that is, the DA regimen of 3+7. 2. The most commonly used chemotherapy regimen for acute lymphoblastic leukemia is the first-line induction regimen, which is usually a 28-day course of treatment. The drugs include cyclophosphamide, vincristine and so on. 3. The chemotherapy for chronic leukemia patients is not divided into courses, and the drugs are continuously given orally, such as imatinib. However, the number of days of leukemia chemotherapy program is not set in stone in the clinic, and should be adjusted at any time according to the changes in the patient’s blood picture during the course of chemotherapy, such as leukemia patients with severe bone marrow suppression during the course of chemotherapy, it is necessary to shorten the duration of chemotherapy accordingly to avoid life-threatening infections and hemorrhages due to severe infections and hemorrhages. Leukemia is treated differently due to different physical conditions and types of patients, so the treatment methods are different and should be standardized under the guidance of doctors.