Objectives : We recently have reported that constituents of OMC-2010 have an immuno-modulatory effects via inhibiting tumor necrosis factor (TNF)-alpha and interleukin (IL)-5. In this study, based on previous data, we investigated the effects of combinations with each OMC constituents on splenocyte cytotoxicity, cytokine productions, and ovalbumin (OVA) induced experimental allergic asthma. Methods : Mouse splenocytes were pre-treated with ethanol extract of constituents of Rehmannia glutinosa (RG), Pinellia ternata (PT), Schisandra chinensis (SC). We made 4 combinations using RG, PT, and SC (A;1:1:1, B;2:1:1, C;1:2:1, D;1:1:2). The cells were pretreated with A, B, C, or D for 1 h, then stimulated with lipopolysaccharide (LPS, $1{mu}g/ml$) for 48 h. Then the cells were harvested for real-time reverse transcription polymerase chain reaction to detect cytokine productions. Then using effective combination from RG, PR and SC, we administrated the combination orally, then challenged with OVA to induce asthma. Then we analyzed the airway hyper-reactivity (AHR), lung histology and lung TNF-${alpha}$ and IL-5 mRNA. Results : A. B. C. and D did not showed significant cytotoxicity on splenocytes. Pre-treatment of A inhibited the expression of TNF-${alpha}$ and IL-5 significantly, but not B, C, and D. In experimental asthma, administration of A significantly inhibited the increase of AHR, lung damage, TNF-${alpha}$ and IL-5 expression. Conclusions : Theses results could suggest that inhibitory effects of the ideal combination with RG, PT and SC (1:1:1) could be applied to treatment of asthma and study of asthma mechanisms.