A healthy immune system has two pathways – Th1 and Th2, and it is necessary for these two pathways to be balanced. The immune system of allergic people has an imbalance of TH2 excretion and lack of TH1 excretion. Clinical studies have shown that allergic patients have significantly higher serum IgE, more mast cells and more IgE receptors on the cell membrane. Helper T cells and their cytokines play an important regulatory role in the composition of IgE. According to the variety of cytokines excreted, the helper cells are divided into two subgroups, Th1 and Th2. The cytokines excreted by Th2 cells play a major role in antibody formation and allergic reactions. In healthy conditions, Th1 and Th2 are in balance with each other and are regulated by helper T cells at the same time. This leads to an increase in IgE concentration in the serum, thus triggering allergy. Probiotics can stimulate the production of IL-12, IFN-γ and other cytokines, strengthen the regulatory ability of immune T cells, and then inhibit the excessive activation of Th2 cells, and maintain the balance of Th1 and Th2 to reduce allergic reactions. 2. Anti-allergic probiotics can reduce the immunogenic factor IgE and effectively block the combination of allergens and immunogenic factor IgE antibodies, directly blocking the allergic biological chain from the root of immunity. 3. Anti-allergic probiotics can enhance the excretion of immunoglobulin IgA, and enhance the barrier function of skin appearance, whistle tract and digestive tract against the invasion of external allergens.