The dangers of breathing through the mouth are divided into three areas. The first aspect is the impact on the respiratory system, the impact on the oral cavity, and may also affect the facial appearance. Under normal circumstances, breathing through the nose will have a certain warming and humidifying effect on the outside air, as well as filtering large particles of dust and filtering germs through the nasal cilia, etc. If you breathe through the mouth, the unfiltered air will enter the lower airway directly from the pharynx, which may cause respiratory diseases, such as inflammation of the lungs and so on. Moreover, this air breathed through the mouth will irritate the mucous membrane of the throat and irritate the airway for a long time, which will lead to cough, sore throat, chronic pharyngitis and other problems. The second aspect is the impact on the oral cavity. Long-term breathing through the mouth is likely to cause inflammation, ulcers, dental caries and uneven integration of teeth, and may lead to dry mouth, dry throat and discomfort in the throat. The third aspect is that breathing through the mouth for a long time may lead to changes in facial appearance, such as long and narrow face and protruding mouth, which may cause changes in facial appearance.