If the child is sleeping with his mouth open, it is possible that the nasal secretions are clogging the nasal cavity and the parents can help the child clean it up. 2. If the child is obese and the airway at the throat is narrowing, the parents should arrange the child’s diet reasonably and increase the amount of exercise to help the child lose weight. 3. If your child is suffering from adenoid hypertrophy, the adenoids must be removed and the nose will be ventilated before you can correct sleeping with your mouth open. 4, if your baby has rhinitis and the nose is not ventilated, parents should take your baby to the hospital for examination and treatment and the nose will be ventilated before you can correct sleeping with your mouth open.