Children occasionally open their mouths to sleep generally no serious harm, but long-term open mouth sleep, may lead to oral dryness, cause local inflammation, induced adenoid facial features. 1. lead to oral dryness: small children sleep with their mouths open for a long time, when breathing, it is easy to cause the mouth to inhale more air, which may lead to oral dryness, especially in the throat area tends to be abnormally dry performance. 2. cause local inflammation: small children who sleep with their mouths open for a long time, easily lead to bacteria, viruses and other pathogenic microorganisms invasion, is likely to induce local inflammation, which may cause bronchitis, chronic pharyngitis and other diseases. 3. induced adenoid face: small children sleep with their mouths open, may be caused by adenoid hypertrophy. If you sleep with your mouth open for a long time, it is likely to lead to abnormal development of the facial and jaw parts, which may cause adenoid face, such as thickening of the lips, teeth are not aligned, jawbone becomes normal, etc., resulting in facial aesthetics affected. Children sleeping with their mouths open for a long time has some harmful effects, it is recommended to consult a doctor as soon as possible to clarify the causes, and then be guided by the doctor to treat and regulate.