The aim of the study is comparative assessment of the influence of separated and combined use of pyrimidine and 3-hydroxypyridine derivatives — xymedon and mexidol on the bone marrow hemopoiesis and peripheral blood quantitative indicators in rats with Walker-256 carcinoma at the doxorubicin and paclitaxel chemotherapy. Materials and Methods. Experiments have been carried out on 83 Wistar female rats of weight 150-250 grams. Doxorubicin in a dose of 4mg/kg and paclitaxel in a dose of 6mg/kg were administered intraperitoneally on the 11th day of experiment. Xymedon (100mg/kg) and mexidol (50mg/kg) were administered separately and in combination with each other, starting with the 11th day of experiment for 10 Says. We estimated myelograms and peripheral blood changes on the 14th and 22d day of the experiment. Results. Xymedon normalized differentiation of granulocytopoiesis cells more effectively than mexidol and reduced severity of erythrocytopenia on the 14th day of the experiment. Combination of xymedon and mexidol accelerated granulocytes differentiation more effectively than separated use of these medicines. It was accompanied by more effective increase of neutrophils number in peripheral blood. Despite the increase of poly-chromatophil normocytes number in bone marrow to the 22d day, the erythrocytes number in blood was not differed from one at separated use of these medicines. Conclusion. Myeloprotective effect of xymedon exceeds the effect of mexidol one. The combination of xymedon and mexidol accelerates granulocytes differentiation more effectively than separated use of these medicines.