Open mouth snoring may be caused by obesity, nasal diseases, jawbone abnormalities and other factors. 1. Obesity: Obese people’s neck or soft palate is easy to accumulate fat, resulting in the upper airway is narrower than normal. Muscle relaxation during sleep, easy to produce eddy currents in the narrow part of the airway, resulting in airway blockage above the soft palate, will make the obese people open their mouths to breathe. In addition, the eddy current will also impact the soft palate, resulting in open mouth snoring during sleep. 2. Nasal diseases: when there are acute and chronic rhinitis, acute and chronic sinusitis, deviated nasal septum, nasal polyps and other nasal diseases, a large amount of secretion or superfluous organisms, resulting in the occupation of the nasal passages, they will open their mouths to breathe in their sleep and the soft palate will be easily impacted by the airflow, which will lead to open-mouthed snoring. 3. Abnormalities of the jaws: In the case of maxillofacial deformities (such as mandibular retraction, deep overjaw, etc.), the airway is narrowed and the nasal passage is not well ventilated, so the patients will open their mouths and breathe in order to minimize the discomfort. The soft palate vibrates due to the impact of the airflow, and the patient snores with the mouth open. It is important to note that if you snore with your mouth open during sleep, it is recommended that you seek prompt medical attention to identify the cause of the problem and treat it under the guidance of your doctor.