In terms of physiological status, children, especially infants and young children, have immature respiratory organs, poor adaptability to changes in the external environment, short respiratory tract, low immune function, etc., making children more prone to respiratory infections than adults, and the condition is usually more serious. And in some pathological conditions, making children more prone to respiratory infections, such as: 1, low immune function: children with low immune function are prone to respiratory infections. 2, congenital malformations: especially infants and children with congenital heart disease, congenital stupidity, cleft lip and palate. 3, nutritional deficiency diseases: such as malnutrition, anemia, rickets, zinc deficiency, vitamin A deficiency, etc. 4, asthma, bronchitis. 5.Tonsils enlargement and congestion: bacteria, viruses, etc. can easily stay and invade the tonsils, causing recurrent respiratory infections. 6, environmental factors: In addition to seasonal changes, air conditioning disease in summer is also prone to respiratory tract infections. According to the World Health Organization survey report, whether developed countries, or developing countries, the average urban children suffer from about 4-8 acute respiratory infections per year.