There is no N3 type of leukemia, which may refer to leukemia type M3. M3 leukemia is acute promyelocytic leukemia, and the steps of treatment are general treatment, chemotherapy, and bone marrow transplantation is usually not needed. 1. General treatment (1) Emergency treatment of hyperleukocytemia: leukapheresis is not recommended, hydration and chemotherapeutic drugs such as cytarabine and Zoerythromycin can be given. (2) Prevention of infection: granulocyte deficiency persists after chemotherapy and radiotherapy, and the treatment environment should be kept relatively sterile. Antibiotics such as penicillin can be given if accompanied by infection. (3) Component transfusion support: severe anemia can be oxygenated, transfusion of concentrated red blood cells and so on. (4) Prevention of complications: adequate hydration of the infusion, prevention and treatment of complications such as hyperuricemia, acute renal failure. (5) Maintain nutrition: maintain water and electrolyte balance. Give high-protein, high-calorie, easy-to-digest foods such as yogurt and soy milk. 2. Chemotherapy (1) Induction of remission treatment: mostly use all-trans retinoic acid and arsenic such as arsenic trioxide to induce treatment. (2) Post-remission treatment: cerebrospinal fluid examination and prophylactic intrathecal injection, chemotherapeutic agents such as Zoerythromycin and Cytarabine may be used. There may be other treatments for M3 leukemia, and it is recommended to standardize the treatment under the guidance of a doctor. The above drugs are used reasonably under the guidance of doctors, avoid self-medication.