Sleeping with the mouth open is more common in obstructive sleep apnea syndrome, which may also be caused by tonsillar hypertrophy. Some patients have rhinitis, sinusitis, and adenoid hypertrophy, and a few patients have jaw and jaw developmental malformations. It is recommended to visit the ENT and stomatology departments for rhinolaryngoscopy and sleep apnea monitoring to help assess the cause of the disease and to provide targeted treatment. If it is caused by an inflammatory reaction, the patient can choose medication. If it is caused by obstructive sleep apnea syndrome, surgery or long-term ventilator treatment may need to be considered.