Autologous hematopoietic stem cell transplantation is mainly performed for patients with lymphoma, multiple myeloma, and even certain leukemias. As for how long it takes, it usually takes 1 month from the start of the procedure to enter, pretreatment to exit. This 1-month period includes pretreatment, which is a very intensive chemotherapy, through which some bad cells inside the bone marrow are completely killed, and then the bone marrow is supported by transfusing back its own stem cells to create blood, which is relatively safe. The time needed is generally after the leukocytes have risen to normal, and the patient can be discharged after proper care, when the leukocytes are stable, the hemoglobin and platelets are stable, that is, no major infection has occurred, and the hematopoietic function has been rebuilt. The risks are relatively low. It is also a treatment option for most elderly patients, that is, for some elderly leukemia patients aged 50-65.