Some elderly people will open their mouths to breathe when they sleep. The reason is mainly due to congestion and edema of the nasal mucosa, with varying degrees of inflammatory material exudation, resulting in narrower than normal nasal passages. As the airway is not open, elderly people will open their mouths to assist breathing, so that more air can enter the airway to meet the normal volume of gas. It is mainly common in elderly people with different degrees of chronic lesions in the upper respiratory tract, such as adenoid hypertrophy, chronic rhinitis, sinusitis, nasal polyps, deviated nasal septum combined with chronic inflammation, chronic tonsillitis, etc. Symptomatic and etiological treatment can be carried out according to different etiologies.