In particular, d,l-methadone was found to induce apoptosis in HL-60 human myeloid leukemia and CEM human T-cell lymphoblastic leukemia cell lines via downregulation of both X chromosome-linked inhibitor of apoptosis (XIAP) and B-cell lymphoma-extra large (Bcl‐xL)4. Here, XIAP is linked to myeloid leukemia.