Bone marrow is the soft, fatty tissue inside human bones. Stem cells are immature cells in the bone marrow that give rise to all of human blood cells. A bone marrow transplant is a procedure to replace damaged or destroyed bone marrow with healthy bone marrow stem cells. Now a days it is increasingly used as therapy for aplastic anaemia, various haematological malignancies, immunodeficiency syndromes and thalessaemia. "Auto" means "self." Stem cells are removed from patient own body before receive high dose chemotherapy or radiation treatment. After these treatments are done, patient stems cells are put back in their body. This is called a "rescue" transplant. Similar to autologous transplants are syngeneic transplants among whom the HLA-identical twin serves as the donor Autologous bone marrow transplants are preffered for patients who require high-level or marrow ablative chemotherapy to eradicate an underlying malignancy but have healthy, undiseased bone marrow. Autologous bone marrow transplants are also preffered when the immunologic antitumor effect on an allograft is not beneficial. Autologous bone marrow transplants are used most frequently to treat breast cancer, non-Hodkin's lymphoma and Hodgkin's disease.