IGHE and Alzheimer disease: An increasing number of studies have demonstrated that the therapeutic effect mechanism of herbal drugs is linked with gut microbiota.[25] Many clinical studies that have reported the efficacy of herbal formulas in treating AD have observed skin symptoms using SCORAD and EASI and assessed the modulation of immune biomarkers such as serum IgE, eosinophil counts.[24] To date, no clinical studies have evaluated the efficacy of herbal drugs on gut microbiota in patients with AD.