Babies sleeping with their mouths open mainly consider the following two reasons: 1. Adenoid enlargement: it grows gradually with age after birth, and it is a period of vigorous proliferation from 2 to 6 years old, and gradually shrinks after 10 years old. Adenoid hypertrophy is a pathological hyperplasia of the adenoids due to repeated stimulation of inflammation, which causes nasal congestion, open-mouth breathing symptoms, especially aggravated at night, sleep snoring, sleep disturbance, children often turn over from time to time, more obvious when lying on their backs, and in severe cases, apnea can occur. The disease is most often seen in children and is often combined with chronic tonsillitis and tonsillar hypertrophy. Within ten years of age, conservative treatment can be given by spraying the nose with physiological sea saline every day, and if necessary, inhaled glucocorticoids can be used to treat the symptoms and prevent severe hypoxia. 2, rhinitis: also easy to cause open mouth breathing can not relieve the symptoms of nasal congestion, first of all, you should check the allergens, avoid contact with allergens, this situation can be completely relieved, while the child used sea saline and with the inhaled glucocorticoids, then can completely improve the situation of open mouth breathing, the above two conditions need to be given timely treatment and improvement, otherwise it is easy to form adenoids These two conditions need to be treated and improved in a timely manner, otherwise, adenoids will easily form, resulting in damage to the child’s facial appearance and causing mental impairment due to insufficient oxygen supply to the brain.