When pretreatment of high-dose chemotherapy for bone marrow transplantation, the use of drug dosage should be based on the use of different drugs and different types of diseases, such as cyclophosphamide total dose can be used up to about 120mg/kg. 1. Cyclophosphamide: a commonly used immunosuppressant, often used in conjunction with high-dose whole-body irradiation, the classic pretreatment regimen is whole-body irradiation of 10Gy plus a total dose of 120mg/kg of cyclophosphamide, commonly used in children’s acute leukemia bone marrow transplantation before the pretreatment. 2. Leucovorin: used together with cyclophosphamide. Leucovorin 16mg/kg plus cyclophosphamide total dose 120mg/kg. 3. Epigallocatechin: the maximum dose of epigallocatechin can be 60mg/kg in clinic, often combined with systemic irradiation. 4. Levophenylalanine nitrogen mustard: before bone marrow transplantation, the dose of levophenylalanine nitrogen mustard can be up to 110mg/kg, often combined with total body irradiation. Bone marrow transplantation pretreatment high-dose chemotherapy, in addition to the drug category, but also with the patient’s physical condition, type of disease, therapeutic effect, joint use of drugs and other circumstances related to the above data is for reference only, can not be used as a clinical guide to the use of drugs. The specific dose should be administered under the guidance of the clinician to avoid adverse effects.