This study was done to evaluate the antiallergic effects of Naenghyohwan(NHH). Cytotoxic activity for lung fibroblast cells, cytokines transcript expression of IL-1, IL-4, IL-5, TNF-${alpha}$, IL-6, IL-10, TGF-${eta}$1, IFN-${gamma}$, production of IL-4, IL-10. IFN-${gamma}$, IgE in anti-CD40mAb plus rIL-4 stimulated murine splenic B cells and the production of histamin released in mast cells, and the expression of histamine release factor(HRF) in splenic B cells were measurd. The following results were obtained. NHH did not showed cytotoxicity in fibroblast cells. NHH increased the gene synthesis of TNF-${alpha}$, IFN-${gamma}$(m-RNA). NHH decreased the gene synthesis of IL-1${eta}$, IL-4, IL-5, IL-6, TGF-${eta}1$(m-RNA). NHH decreased the appearance of IL-4, IgE significantly. NHH increased the appearance of IL-10. IFN-${gamma}$ significantly. NHH decreased the proliferation of B cells significantly. NHH decreased the appearance of histamin expression of HRF in mast cells significantly. The results suggest NHH is effective against the allergies. Continued studies of the antiallergic effects of NHH are urged.