A stem cell transplant also called a blood or marrow transplant is the injection or infusion of healthy stem cells into your body to replace damaged or diseased stem cells. A stem cell transplant may be necessary if your bone marrow stops working and doesn't produce enough healthy stem cells. This procedure also may be performed if high-dose chemotherapy or radiation therapy is given in the treatment of blood disorders such as leukemia, lymphoma, multiple myeloma or sickle cell anemia. A stem cell transplant can help your body make enough healthy white blood cells, red blood cells or platelets, and reduce your risk of life-threatening infections, anemia and bleeding. Although the procedure to replenish your body's supply of healthy blood-forming cells is generally called a stem cell transplant, it's also known as a bone marrow transplant, peripheral blood stem cell transplant or an umbilical cord blood transplant, depending on the source of the stem cells