Background: Interleukin (IL)-33 is involved in development of allergic inflammation, and soluble ST2 (sST2) is a fusion protein that neutralizes IL-33 activity. Therefore, we aimed to investigate whether Anti-IL-33 and sST2 reduced inflammation in asthma. Methods: Fourty BALB/c mice were used. In group A (control group, n=6), mice were sensitized and challenged with saline. Group B [ovalbumin (OVA) group, n=6] mice received subcutaneous and intranasal OVA challenge. In group C (control goat IgG group, n=6), mice were injected intraperitoneally with control IgG before OVA challenge. In group D (anti-IL-33 group, n=8), anti-IL-33 was injected intraperitoneally before challenge. In group E (control human IgG group, n=6), mice were injected intraperitoneally with control IgG before OVA challenge. In group F (sST2 group, n=8), sST2 was injected intraperitoneally before challenge. We evaluated the number of eosinophils, neutrophils, lymphocytes and macrophages in bronchoalveolar lavage (BAL) fluid; airway hyperresponsiveness (AHR) to methacholine; and IL-4, IL-5, IL-10 and IL-13 in BAL fluid. Results: Anti-IL-33 and sST2 significantly reduced the number of eosinophils in BAL fluid. IL-4, IL-5, IL-10, and IL-13 in BAL fluid were also significantly decreased after Anti-IL-33 and sST2 treatment. Airway hyperresponsiveness to methacholine was decreased when treated with both Anti-IL-33 and sST2. Conclusions: Anti-IL-33 and sST2 has a therapeutic potential for allergic asthma.