Many people will have a feeling of dry mouth in the middle of the night, once or twice occasionally, may be for the environment, or eating, cold-related. If often, it may be caused by diseases and other reasons: 1, environmental factors: indoor too dry, such as air conditioning and heating lead to indoor environment is too dry, in this high heat, dry environment, resulting in human body moisture loss, dry mouth. Eating food with high salt content, you will also feel dry mouth. 2, disease factors: (1) cold will lead to dry mouth. (2) One of the typical symptoms of diabetes is thirsty and drinking at night, which often manifests as dry mouth. (3) Dryness syndrome, when the pathogenic factors attacked the salivary glands, resulting in its secretion reduction, easy to lead to dry mouth and tongue. (4) Oral disorders, rhinitis and snoring can lead to dry mouth. (5) Patients with hyperthyroidism often have dry mouth due to hormonal reasons. (6) Anemia, liver fire, and gastrointestinal disorders can also lead to dry mouth. 3, drug factors: certain drugs can cause dry mouth. For example, anti-psychotic, anti-depressant drugs and certain anti-arrhythmic drugs can lead to dry mouth as a side effect. If the symptom of dry mouth occurs in the middle of the night, we should first consider diet and environmental factors, and secondly, we should consider pathological changes and side effects of drugs. It is recommended to go to the hospital for timely examination and scientific diagnosis and treatment if this symptom occurs frequently.