Methods of treating diseases of the nervous system by administration of compositions having the neurological therapeutic activity of human erythropoietin are disclosed. These compositions include therapeutic agents such as peptides, peptide dimers, polypeptides, and proteins that have the full range of biological activity of human erythropoietin or only certain biological activities of erythropoietin. Improved therapeutic regimens where the erythropoietin is administered at concentrations below those required to stimulate hematopoiesis are also provided.