We often encounter children with recurrent colds, recurrent bronchitis, or recurrent coughs and wheezing in our clinics. Children are suffering and parents are anxious. Many parents ask about the medicine to enhance resistance. The following is an introduction to the commonly used immunomodulators at home and abroad: I. Meiyuan Kang Fu ABD active factor (main ingredient glutathione) has been widely used in Europe and the United States and other countries, and has now entered the Chinese market. ABD Active Factor is rich in immunoglobulin and lactalbumin, which can rapidly activate the immune system of infants and children. In addition, glutathione has a moderating effect on allergic diseases, such as allergic asthma, allergic rhinitis and urticaria, etc. Second, pidomod is a human functional synthetic high-purity dipeptide, which can promote non-specific and specific immune response, and can act on different stages of immune response. Panfluxol is extracted from 8 common respiratory pathogenic bacteria, with specific and non-specific immune stimulating effects, and can improve the immune response in children with recurrent respiratory tract infections. BCG vaccine is an extract of attenuated BCG vaccine and its membrane components, which can regulate the immune function of the body. V. Propecia is a blood product that can improve the immune function of children for a certain period of time, but there are certain risks because the product is a blood product. Sixth, Chinese medicine preparations Commonly used are astragalus, yu pingfeng, spleen powder and so on. If children have recurrent respiratory infections, parents can choose the above immunomodulatory preparations according to their own situation and that of their children.