Dry mouth is usually a temporary condition caused when the salivary glands don't produce enough saliva. It's a common side effect of many prescription medications and a symptom of certain diseases.
Though it can occur at any age, it is more common in older people, affecting 30% of those 65 and older.
Dry mouth isn't life-threatening, but it can be extremely bothersome and can have negative effects on dental health. The medical term for dry mouth is xerostomia.