The purpose of this study reported here was to investigate the ability of Bu-Zhong-Yi-Qi-Tang (BZYQT), known to elevate hematopoietic functions, to protect mice undergoing treatment with whole body single gamma-irradiation. BZYQT was given (25 mg/kg B.W.) intraperitoneally at 36 and 12 hours before irradiation and 30 minute and 24 hours after irradiation. Recovery of neutrophil and lymphocyte counts was significantly stimulated by extract of BZYQT. Stimulated recovery by the extract from the BZYQT was also observed in thrombocyte. However, the anti-radiation effect of erythrocyte, hemoglobin and hematocrit was not as significant as that of leukocyte. Further studies are needed to better characterize the protective nature of BZYQT extract and its ingredients.