What causes long-term dry mouth?

Dry tongue is a typical non-specific symptom, which can be seen in many diseases. First, dry tongue caused by dry climate, low air humidity or too little drinking water can be considered. This situation belongs to a relatively normal physiological phenomenon. In addition, several pathological conditions should be considered. Second, some endocrine system diseases can also cause dry mouth, such as diabetes patients often show dry mouth, thirst, excessive drinking, polyuria and other symptoms. Third, dry mouth can be seen in some autoimmune diseases, such as Sjogren's syndrome can show dry mouth, nasal and eye symptoms.