Dry mouth, known medically as xerostomia, is a common condition that affects many adults. It occurs when the salivary glands in the mouth do not produce enough saliva needed for normal functions like chewing and swallowing. People with dry mouth typically experience uncomfortable symptoms such as
A sore throat
Cracked lips
Difficulty speaking
An overall sense of thirstiness
In some cases, dry mouth can be a sign of an underlying medical condition or side effect from medications.
1The following are some well studied causes of dry mouth.

Dehydration is a common but oftentimes overlooked cause of dry mouth. This can lead to difficulty speaking, swallowing, and even an unpleasant taste in the mouth. Dehydration occurs when your body does not have enough water or fluids for normal functioning. It can happen when you do not drink enough fluids or due to excessive sweating from physical activity or being exposed to hot temperatures.
The most common symptom of dehydration is thirst; however, it can also cause dry skin and eyes, fatigue, dizziness and confusion. Additionally, it can decrease saliva production and lead to dry mouth. People may experience this symptom after exercising intensely on a hot day without taking time to rehydrate during their activities.