In order to evaluate the antiallergic effects of Kamiohihyosan(KCHS), studies were done. We measured the cytotoxic activity for lung fibroblast cell, cytokines transcript expression, production of IL-4, IL-10, IFN-γ, proliferation of B cell in anti-CD40mAb plus rIL-4 stimulated murine splenic B cells. The results were obtained as follows: KCHS was not showed cytotoxicity in the fibroblast lung cell, KCHS increased the gene synthesis of INF-γ, TNF-α, IL1-β, IL-6, IL-10(m-RNA), KCHS decreased the gene synthesis of IL-4, IL-5, TGF-β(m-RNA), KCHS decreased the appearance of IL-4, IgE significantly, KCHS increased the appearance of IL-10, IFN-γ significantly, KCHS decreased the proliferation of B cell significantly, The facts above prove that KCHS is effective against the allergy. Thus, I think that we should study on this continuously.