The major side effect of high-dose chemotherapy is damage to the bone marrow.
Bone marrow is the material inside the bones that makes blood cells.
All three cell types are needed for normal body function. The parent cells that produce the red cells, white cells and platelets are called stem cells. Stem cells are found in the bone marrow and in the circulating blood. In order to avoid the damaging side effects of high-dose chemotherapy, bone marrow or stem cells are removed from the patient and frozen for future use. Afterwards, the patient receives high-dose chemotherapy.