Bone marrow aspiration is of help in several situations: (1) to confirm the diagnosis of megaloblastic anemia; (2) to establish the diagnosis of leukemia or multiple myeloma; (3) to determine whether deficiency of one or more of the peripheral blood cellular elements is due to a deficiency in the bone marrow precursors (bone marrow hypoplasia); (4) to document a deficiency in body iron stores in certain cases of suspected iron deficiency anemia; and (5) in certain cases, to demonstrate metastatic neoplasm or some types of infectious disease (culture or histologic sections may be preferred to routine Wright-stained smears).