The objective on this study was to investigate effect of KH, which was composed of 9 kinds of oriental herbs tonifing the blood, against toxicity of 5-flurouracil(FU) through animal study. Reduction of WBC and platelet after treating S-FU was significantly recovered by KH. KH also rehabilitated immune gene expression of interleukin-2(IL2) and $Interferon-{gamma};(IFN-{gamma})$ by RT-PCR. In addition, in situ hybridization of spleen showed that KH treatment increased mRNA expression of IL2. In addition to the immune action, antitumor activity on 5-FU was not affected by KH treatment. In conclusion, our study demonstrated that KH alleviated damage of hematopoiesis system induced by f-FU without toss of antitumor activity.