Bu-Zhong-Yi-Qi- Tang extracts is a traditional oriental medicine in a mixture type exhibiting strong anti-bacterial, analgesic, and chemopreventive activities. In this study, we have evaluated effects of the total and polysaccharide fraction of Bu-Zhong-Yi-Qi- Tang extracts on the T cell proliferation, cytokine production, and induction of IL-2 receptor and MHC class n. For this experiment, we established CD4$^{＋}$ CD8$^{[-10]}$ T cell line producing IL-2 and IFN-${gamma}$ when stimulated with ovalbumin antigen in the presence of antigen presenting cells. The significant effect of Bu-Zhong-Yi-Qi-Tang on antigen-induced T cell proliferation in the presence of antigen presenting cells was observed. The proliferation and IFN-${gamma}$ production of T cells was increased in a dose dependent manner, and expression of IL-2 receptor on T cells and MHC class n molecule on antigen presenting cells was also induced in the presence of Bu-Zhong-Yi-Qi-Tang polysaccharide fraction. It was demonstrated that polysaccharide fraction of Bu-Zhong-Yi-Qi-Tang stimulates the antigen-induced T cell proliferation and the production of IFN-${gamma}$ possibly through the increase of IL-2 receptor and MHC class n expression. Therefore Bu-Zhong-Yi-Qi-Tang can be regarded as a natural and useful immunomodulator having a relatively nonotoxic property. Further studies are needed to better characterize the nature of Bu-Zhong- Yi-Qi-Tang extract.