5. Diabetes
Dry mouth at night is a frequent complaint among people with diabetes. Elevated blood sugar levels make the kidneys work overtime to flush out the excess, causing the body to lose more fluids.
This fluid loss can result in dehydration and a dry sensation in the mouth during sleep.

6. Bile Reflux
When bile backs up into the stomach due to weakened liver function, it can disrupt sleep and cause digestive discomfort.
Bile reflux may also contribute to dry mouth at night. Addressing liver health is key to managing this problem.

7. Fever
A rise in body temperature from fever causes fluid loss, often leading to a dry or burning feeling in the mouth.
Staying hydrated and resting can help manage these symptoms, along with fever-reducing treatments.

8. Overactive Thyroid (Hyperthyroidism)
An accelerated metabolism caused by hyperthyroidism increases the body’s fluid needs and stimulates the nervous system excessively.

This can leave you waking up with a persistently dry mouth during the night.

If you often wake up with a dry mouth, it’s worth reviewing your daily habits—what you eat, how much water you drink, and your oral hygiene routine. Should the problem continue, consulting a healthcare professional is the best way to rule out more serious conditions.