Fever is often caused by the invasion of the respiratory mucosa by pathogens, resulting in an inflammatory reaction of the respiratory mucosa. The main manifestations are congestion and edema of the respiratory tract mucosa, exudation of inflammatory substances, and even rupture of the respiratory tract mucosa. The airflow generated during breathing passes through the respiratory mucosa and impinges on the mucus exuded from the respiratory tract, resulting in loud or even rough breathing. It is recommended to test the blood routine, take chest X-ray and pathogen culture of respiratory mucus if necessary, to clarify the cause and treat the symptoms.