Pediatric capillary bronchiolitis is an acute infection of the lower respiratory tract that is more common in infants and young children, mainly in the capillary bronchi, and is most common in infants under 2 years of age, with wheezing, shortness of breath, and trismus being the main clinical features. Pure capillary bronchitis that does not involve the alveolar and interalveolar walls is more difficult to detect clinically, so it is considered a specific type of pneumonia in China, called stridor pneumonia. The onset of the disease is related to the anatomical characteristics of the bronchi of this age. The tiny lumen is prone to obstruction by mucous secretions, edema and muscle contraction, and can lead to emphysema or atelectasis. Pediatric capillary bronchitis can be caused by different viruses. Respiratory syncytial virus (RSV) is the most common pathogen. In addition, parainfluenza virus (type 3 is more common), adenovirus, influenza virus, eutherovirus and rhinovirus can cause bronchiolitis, and a few are caused by Mycoplasma pneumoniae. Clinical manifestations: Persistent dry cough and episodes of dyspnea often appear 2 to 3 days after upper respiratory tract infection. The disease is characterized by simultaneous occurrence of cough and stridor. The symptoms vary in severity, and the dyspnea develops very quickly in severe cases. The body temperature varies, and most of them are not febrile. Due to emphysema and chest expansion, the abdomen is compressed, which often affects milk sucking and diet. The respiratory rate is about 60-80 breaths/minute, or even more than 100 breaths/minute, and the pulse is fast and thin, often reaching 160-200 breaths/minute. There are obvious nasal fan and trigeminal signs. There is no specific treatment for capillary bronchitis, and while mild cases of capillary bronchitis have a tendency to heal spontaneously, severe cases are often life-threatening. At present, nebulization therapy is a simple and effective method with few side effects. Oxygen therapy should be given promptly in case of hypoxic manifestations.