Objectives: Oriental pear was used as traditional remedies for respiratory diseases like cough and asthma etc. The purpose of this study was to observe the effects of preventing asthma by the combination of phenolic compound extracted from pear and herbal drugs. Methods: In order to study the effects of preventing asthma by the combination of phenolic compound extracted from pear and herbal drugs(Platycodon grandiflorum, Prunus armeniaca) on allergic asthma, mice were pre-treated by oral administration of the solution before antigen sensitization for 10 days and 20days. And 2 days later, mice were actively sensitized with a subcutaneous injection of ovalbumin and 13 days later, they were provoked with ovalbumin aerosols. The experimental groups were divided 6groups(10d1P, 10d2P, 10d4P, 20d1P, 20d2P and 20d4P) by meditation quantity and period. We measured isometric contractile responses to acetylcholine(ACh) and KCl in the isolated tracheal smooth muscle(TSM), IL-4, eosinophil and lymphocyte in bronchoalveolar lavage fluid(BALF), IgE in serum, WBC, RBC and hemoglobin in blood. Results: Contractile responses of TSM to ACh, the sensitivity of TSM to Ach and the maximal contractile response of TSM to KCl were decreased by direct proportion of meditation quantity. Eosinophil and IL-4 level in BALF were more significantly decreased, and IgE level in serum was more significantly increased in 10d4P and 20d4P group than the control group. Conclusions: Based on the above results, it is assumed that oral administration of the combination of phenolic compound extracted from pear and herbal drugs(Platycodon grandiflorum, Prunus armeniaca) can help the preventing effects of allergic asthma.