IGHE and allergic disease: Synbiotics are a combination of probiotics and prebiotics.[16,17] Probiotics, prebiotics, and synbiotics can ameliorate the host immune system via gut ecosystem and may be beneficial for the treatment of allergic diseases such as asthma.[18] Some animal experiments have shown that probiotics can effectively inhibit IgE production and the accumulation of eosinophils.[19–21] Probiotics also show effects in the prevention and treatment of allergic diseases.[22,23]