What Are the Causes of Dry Mouth During Sleep?

The condition of dry mouth, also called cotton mouth, is called xerostomia 1. Dry mouth during sleep is caused by a variety of factors including dehydration, a dry environment, signs of illness or side effect of medication 1.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.


When there is a low level of water in the body, less saliva is produced, producing dry mouth 1. Drinking plenty of water before going to bed will help you stay hydrated and avoid dry mouth while sleeping 1.

Open mouth

Sleeping with the mouth open causes the mouth to dry faster because moisture from your mouth is lost to the air 1. Chin straps are available to keep the mouth closed during sleep.

Dry environment

Low humidity in the air causes dry mouth during sleep 1. Using a humidifier can moisten the dry air that flows through the throat and nose.


Dry mouth can be a physical symptom of anxiety or stress 1.


Dry mouth can be a sign of an impending disease 1. Diseases that affect the salivary glands include lupus, diabetes, infections and stone formation in the salivary ducts.

Side effects of medication

Taking medication can cause dry mouth 1. Medication causes a gland dysfunction, which reduces the production of saliva.