Objective : The purpose of this study was to investigate the effects of Gamisagunja-tang(GS) on the airway hyper-reactivity (AHR), cytokine production and T cell activation during the ovalbumin (OVA)-induced allergic asthma in mice. Materials and Methods : BALB/c mice were sensitized and challenged with 100 mg of OVA and 1 mg of aluminum potassium sulfate intraperitoneally on days 1 and 7. On day 14, mice were challenged on 3 consecutive days with 5% OVA. AHR and bronchoalveolar fluid (BALF), total inflammatory cell count and the production of cytokines were measured. Results : GS significantly suppressed the infiltration of inflammatory cells in the lung tissue and AHR. GS significantly down regulated the production of IL-4, IL-5 and increases of $INF-{gamma}$ in BALF. GS reduced the population of eosinophils from lung and spleen in OVA-induced allergic asthma. GS reduced the population of $CD4^{+}$ $CD69^{+}$ $CD25^{-}$ T cells in OVA-induced allergic asthma Conclusion : These results suggest that GS may inhibit the production of IL-4, IL-5 and infiltration of eosinophils and be beneficial oriental medicine for allergic asthma.