Objective: This study was performed to investigate the effects of YTT on allergic bronchial asthma. Methods: The mice were divided into 4 groups induced the allergic bronchial asthma : Three groups(YTT-1, YTT-2, YTT-3) treated YTT and non-treated group(Control). Three oral administration of the herbal solution of YTT were carried out 1 time a day for 2 weeks before antigen sensitization. 2 days later, the mice were sensitized with a subcutaneous injection of ovalbumin(OA) and then 13 days later they were provoked with OA aerosols. Then the cell numbers in bronchoalveolar lavage fluid(BALF), serum level of IgE, WBC, RBC and HGB were measured. Results: 1. On the neutrophil in BALF, groups of YTT-2 and YTT-3 are significantly increased compared with the control group. 2. On the eosinophil in BALF, groups of YTT-1 and YTT-3 are significantly decreased compared with the control group. 3. On the lymphocyte in BALF, YTT-3 group is significantly increased compared with the control group. 4. On the macrophage in BALF, groups of YTT-1 and YTT-3 groups tend to increase. 5. On the serum IgE, groups YTT-1, YTT-2 and YTT-3 are significantly decreased compared with the control group. 6. On WBC in blood, groups of YTT-2, YTT-3 are significant1y decreased compared with the control group. Conclusions: Based on the above results, it is assumed that the oral administration of YTT can help the treatment of allergic bronchial asthma.