Abstract: The invention relates to novel compositions and to methods for the pulsed administration of compositions to a patient or to cells in vitro for the treatment of human blood disorders. Compositions contain chemical compounds that stimulate the expression of fetal hemoglobin and/or stimulate the proliferation of red blood cells, white blood cells and platelets in patients and ex vivo for reconstitution of hematopoiesis in vivo. These methods are useful to treat or prevent the symptoms associated with anemia, sickle cell disease, thalassemia and other blood disorders. The invention also relates to methods for the pulsed administration of compositions to patients for the treatment and prevention of cell proliferative disorders including deficiencies such as cytopenia and malignancies such as viral-induced tumors, other forms of neoplasia and for expansion of cells for hematopoietic transplantation. Pulsed administration has been shown to be more effective than continuous therapy in patients tested.