Baby sleep open mouth is generally normal, but need to be alert to rhinitis and other diseases that cause nasal congestion may be. 1. Normal: general baby at a younger age, the nasal cavity is narrower, the nasal passage is short, may be because the nasal function is not yet well developed, thus uneven breathing, there may be the phenomenon of sleeping open-mouthed, is generally a normal phenomenon. 2. abnormal: the baby sleeps with his mouth open, and breathe through his mouth, but also need to be vigilant about rhinitis and other diseases may lead to increased nasal secretions, resulting in nasal congestion performance. This situation is certainly not normal, can be timely otolaryngology consultation, improve the nasopharyngoscopy and other related examinations to be targeted treatment after a clear diagnosis. Baby sleeping with mouth open is generally normal, but if there is snoring, nasal congestion, runny nose and other manifestations, it is not normal. It is recommended to consult an ENT clinic in time and follow the doctor’s instructions for targeted treatment.