Capillary bronchitis is an inflammation of the capillary bronchi, commonly known as wheezing pneumonia, is a respiratory tract infection specific to infants and children under 2 years of age, with a high incidence in winter and spring, and a peak age of 2-6 months for small infants. Pathogenesis: mainly viral infections, more than 50% are respiratory syncytial viruses. Other viruses are parainfluenza virus, adenovirus, influenza virus, enterovirus, and Mycoplasma pneumoniae. The course of the disease is prone to combined bacterial infection, the prevalent season is winter and spring, the early stage is easy to ignore, the disease is serious, the death rate is 1~3%. Symptoms: persistent dry cough and episodes of wheezing often appear 2~3 days after upper respiratory tract infection, cough and wheezing occur simultaneously as the characteristics of the disease, but cough symptoms are not as obvious as wheezing. The most dangerous period of the disease is 48-72 hours after the onset of cough and dyspnea. In severe cases, the disease develops into heart failure and respiratory failure. Principles of treatment: 1) supportive treatment, such as oxygen therapy, rehydration, nebulization and sputum aspiration; 2) antiviral treatment and appropriate antibiotics in case of combined bacterial infection; 3) symptomatic treatment. Prognosis: Children with capillary bronchitis in infancy are prone to recurrent cough within six months after the disease, and asthma occurs in 1/2 of them in 2-7 years of follow-up. Very few of these coughs and asthma persist for a long time. It is important to pay attention to the exclusion of occlusive capillary bronchitis or congenital cilia immobilization, and if necessary, lung CT or ciliary microscopy is feasible to clarify the diagnosis. Prevention: 1. Pay attention to ventilation in winter and spring; 2. Minimize or avoid going to crowded places; 3. Give children more water appropriately.