IL4 and allergic asthma: Tan et al. found that oral administration of total saponins from P. polyphylla can treat allergic asthma;.its mechanism of action involves suppressing the production of the cytokine IL-4 by Th2 cells and restoring the reduced cytokine IFN-γ by Th1, thereby restoring the local Th1/Th2 cytokine balance, indicating that total saponins of P. polyphylla can reduce airway inflammation and cellular infiltration and decrease the total IgE level, effectively alleviating the symptoms of allergic asthma (Tan et al., 2017).