Kefiran is a major component of kefir which is a microbial symbiont mixture that produces jelly-like grains. This study aimed to evaluate the therapeutic availability of kefiran on the ovalbumin-induced asthma mouse model in which airway inflammation and airway hyper-responsiveness were found in the lung. BALB/c mice sensitized and challenged to ovalbumin were treated intra-gastric ally with kefiran 1 hour before the ovalbumin challenge. Kefiran significantly suppressed ovalbumin-induced airway hyper-responsiveness (AHR) to inhaled methacholine. Administration of kefiran significantly inhibited the release of both eosinophils and other inflammatory cells into bronchoalveolar lavage (BAL) fluid and lung tissue which was measured by Diff-Quik. Interleukin-4 (IL-4) and interleukin-5 (IL-5) were also reduced to normal levels after administration of kefiran in BAL fluid. Histological studies demonstrate that kefiran substantially inhibited ovalbumin-induced eosinophilia in lung tissue by H&E staining and goblet cell hyperplasia in the airway by PAS staining. Taken above data, kefiran may be useful for the treatment of inflammation of lung tissue and airway hyper-responsiveness in a murine model and may have therapeutic potential for the treatment of allergic bronchial asthma.