What causes nighttime dry mouth?

Updated November 21, 2016

Dry mouth is a condition that most of us have experienced at one time or another and that also goes by the designation of hyposalivation, asialorrhea, and xerostomia, according to Most of us would be reluctant to give our romantic partner a big kiss in the morning before brushing our teeth because morning breath, caused in part by dry mouth, can be quite off-putting. For most people, dry mouth isn't a major concern, but for others it's an ongoing problem.

Salivary Glands

Dry mouth is generally caused by the inability of salivary glands to function efficiently and produce adequate amounts of saliva, according to If you are taking medication, it may be why you are suffering from dry mouth. Medicines that cause dry mouth include muscle relaxants, decongestants, chemotherapy drugs, antispasmodics, and antihistamines. However, there are those who have perfectly functioning salivary glands and aren't taking any medicine at all but still suffer from dry mouth.


We need adequate amounts of saliva because, according to, it prevents infection by controlling fungi and bacteria in the mouth via its antimicrobial action, and it also helps us digest food. Saliva consists of antibodies; mucoproteins, which create the slimy sensation; and enzymes, but is primarily (98 per cent) water. Saliva also plays an important role in the health of our teeth. It reduces the acidity or pH of the waste products that plaque produces. By doing this, it reduces our chance of tooth decay, which can occur courtesy of acid attacks that stem from these waste products. Saliva washes debris out of the mouth. It is believed that this debris, if it stays in the mouth, serves as a food supply for the bacteria found in plaque. If there is damage to dental enamel, saliva provides systemic minerals and fluorides that help replace the minerals of the marred enamel.

Physical Concerns

Dry mouth can pose a significant problem, and not only because it is uncomfortable for the sufferer and may produce bad breath. It can contribute to mouth infections and tooth decay. Dry mouth can also be a red flag for other physical problems, according to If you are diabetic and your disease is poorly controlled, this can result in dry mouth during the night, or dry mouth can be an indicator that you have diabetes. Other diseases that result in dry mouth, not only during the night but also during the day, according to, are bacterial and viral infections and Sjogren's syndrome, all of which have an impact on saliva flow; Bell's palsy; tumours; salivary-gland stones; depression; Parkinson's disease; and HIV/AIDS. If you are going through hemodialysis or radiation, this can cause severe dry mouth.

Get Checked Out

According to, if you are being plagued by chronic nighttime and daytime dry mouth, you may want to undergo a physical examination to determine if you have oral candidiasis, a complication of dental caries, or dental caries, a complication of dry mouth. Dental caries is a process that is destructive and damaging, and causes the decalcification of tooth enamel, leading to cavities. Other conditions that may cause dry mouth include dehydration and salivary gland stones. Dry mouth can be a symptom of cirrhosis, rheumatoid arthritis, diabetes, or thyroid disease.

Vitamin Deficiencies notes that if an individual is lacking in Vitamin B6, iron, zinc, calcium, fibre, or potassium, this can result in nighttime and daytime dry mouth. If you are suffering from a parched, crusty, dry mouth, food can burn the inside of your mouth. You may no longer be able to tolerate acidic or spicy foods.

Mouth Breathers

If you are a mouth breather and your mouth hangs open all night long, this will result in dry mouth.

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About the Author

Cindi Pearce is a graduate of Ohio University, where she received her bachelor’s degree in journalism. She completed both the undergraduate and graduate courses offered by the Institute of Children’s Literature. Pearce has been writing professionally for over 30 years.