Chemotherapy-induced　myelosuppression　and　aplastic　anemia　are　bone　marrow　failure　syndromes　characterized　by　peripheral　pancytopenia　and　marrow　hypoplasia.Few　good　therapeutics　have　been　developed　to　solve　the　problems.We　have　identified　a　novel　peptide(PP),derived　from　serum　albumin,with　a　potent　activity　to　stimulate　hematopoietic　cells　proliferation.Assay　of　proliferation　in　vitro　was　carried　out　with　human　haematopoietic　stem　cells　(CD34+)and　bone　marrow　nucleated　cells　from　healthy　volunteers　and　aplastic　anemia　patients＇＇bone　marrow　(donors),　respectively.