We studied the role of the dopaminergic system in the regulation of erythropoiesis in cytostatic myelosuppressions. During cyclophosphamide and 5-fluorouracil treatment, the state of erythropoiesis precursors, functional activity of cell elements of hemopoiesis-inducing mircroenvironment (secretion of erytropoietic activity, formation of hemopoietic islets) are controlled by dopaminergic structures of the brain. The regulatory effect of CNS is mediated via dopamine receptors on precursors and microenvironmental cells and via modulation of activity of the erythropoietin system. Specific dopaminergic control of hemopoiesis-inducing microenvironment and erythroid precursors is determined by peculiarities of the suppressive effects of the alkylating agent and antimetabolite on the blood system.