Capillary bronchitis is one of the most common acute lower respiratory infections in children, which occurs in winter and can cause localized epidemics. The lesions of capillary bronchitis occur mainly in the small bronchi of the lungs, the capillary bronchi, hence the name “capillary bronchitis”. The pathogen is mainly respiratory syncytial virus, which can account for 80% or more; others are adenovirus, parainfluenza virus, rhinovirus, and influenza virus in that order; a few cases can be caused by Mycoplasma pneumoniae; after infection with the virus, the tiny capillary bronchi become congested, edematous, and have increased mucus secretion, plus necrotic mucosal epithelial cells are shed and block the lumen, resulting in significant emphysema and atelectasis. The inflammation often involves the alveoli, alveolar wall and interstitial lung, so it can be considered a specific type of pneumonia. The pathogen of capillary bronchitis is mainly respiratory syncytial virus, which can account for 80% or more; others are adenovirus, parainfluenza virus, rhinovirus, and influenza virus in that order; a few cases can be caused by Mycoplasma pneumoniae; after infection with the virus, the tiny capillary bronchioles become congested, edematous, and have increased mucus secretion, which, together with the shedding of necrotic mucosal epithelial cells and blockage of the lumen, leads to significant emphysema and pulmonary atelectasis. The inflammation often involves the alveoli, alveolar wall and interstitial lung, so it can be considered a specific type of pneumonia. Capillary bronchitis, unlike ordinary bronchitis or bronchiectasis, has clinical symptoms like pneumonia but with predominant wheezing. The disease occurs mostly in children under 2 years of age, 80% within 1 year of age, and mostly in children under 6 months of age. Typical capillary bronchitis often occurs 2 days to 3 days after the upper respiratory tract infection, with a persistent dry cough and fever, temperature is seen as moderate, low fever, episodes of wheezing as its characteristics, the condition is more serious 2 days to 3 days after the onset of wheezing, wheezing episodes of breathing significantly faster, up to 60 times per minute ~ 80 times or more, and accompanied by prolonged expiration and expiratory wheezing; severe children clearly show nasal stirring and “The child is often irritable and moaning; more severe cases may be combined with heart failure or respiratory failure, most cases can be relieved after treatment, and death rarely occurs. The treatment of capillary bronchitis is based on antispasmodic and symptomatic treatment, preferably nebulized inhalation, can be combined with inhalation of budesonide nebulized solution, terbutaline nebulized solution and ipratropium bromide nebulized solution, the course of treatment for about 7 days; such as severe cases of nebulized inhalation effect is not good can be changed to intravenous infusion of hormones and asthma drugs. The treatment can be supplemented with antiviral therapy, and if there is evidence of bacterial infection, antibacterial drugs can be administered. The prognosis for most cases of capillary bronchitis is good, and the duration of the disease is usually 5 to 10 days. However, it should be noted that children who have suffered from capillary bronchitis are prone to asthma in the future. Through the national epidemiological survey of pediatric asthma and follow-up of children with infantile capillary bronchitis, it was found that 20% to 40% of these children developed pediatric asthma later.