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Dry Mouth



Bernard J. Hennessy

, DDS, Texas A&M University, College of Dentistry

Reviewed/Revised Jan 2024
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Dry mouth is caused by a reduced or absent flow of saliva. This condition can cause discomfort, interfere with speech and swallowing, make wearing dentures difficult, cause bad breath Bad Breath Bad breath is a frequent or persistent unpleasant odor to the breath. Certain diseases produce substances that are detectable on the breath, but these odors are typically mild and not considered... read more (halitosis), and worsen oral hygiene by causing a decrease in the acidity of the mouth and an increase in bacterial growth, which contributes to the development of cavities Cavities Cavities are decayed areas in the teeth, the result of a process that gradually dissolves a tooth’s hard outer surface (enamel) and progresses toward the interior. (See also Overview of Tooth... read more Cavities . Longstanding dry mouth can result in severe tooth decay and candidiasis Candidiasis Candidiasis is a fungal infection caused by several species of the yeast Candida, especially Candida albicans. The most common type of candidiasis is a superficial infection of... read more Candidiasis of the mouth. Dry mouth is a common complaint among older adults.

Causes of Dry Mouth

Dry mouth occurs when the salivary glands (glands in the mouth that produce saliva) malfunction and thus decrease saliva production. There are many causes, including dehydration and mouth breathing (see table ).

The most common causes of dry mouth are

  • Medications and other substances

  • Radiation to the head and neck (for cancer treatment)

Medications are the most common cause overall. About 400 prescription medications and many nonprescription (over-the-counter) medications cause a decrease in saliva production. The most common classes of medications include the following:

  • Medications that have anticholinergic effects (those that block acetylcholine)

  • Antiparkinsonian medications (those used to treat Parkinson disease)

  • Cancer chemotherapy medications

Many commonly used medications have anticholinergic effects Anticholinergic: What Does It Mean? Anticholinergic: What Does It Mean? . Dry mouth is only one among many anticholinergic side effects.

Illegal methamphetamine use has resulted in a disorder called meth mouth, which is severe tooth decay caused by methamphetamine-induced dry mouth. The damage is worsened by the tooth grinding and clenching caused by the drug, the heat of the inhaled vapor, and probably elevated intake of sugary beverages and poor oral hygiene while using this drug. This combination causes very rapid destruction of teeth and a lifetime of dental problems for younger people.

Tobacco use usually causes a decrease of saliva.

Radiation therapy for head and neck cancer can severely damage the salivary glands, often causing permanent dryness. Even low doses of radiation can cause temporary drying.

Evaluation of Dry Mouth

Not all people with a dry mouth need to be immediately evaluated by a doctor. The following information can help people decide whether a doctor’s evaluation is needed and help them know what to expect during the evaluation.

Warning signs

When to see a doctor

People who have warning signs should see a doctor right away. People with extensive tooth decay should have a dental examination. People with a dry mouth but no warning signs and who otherwise feel well may see their doctor within a week or so.

What the doctor does

Doctors first ask questions about the person’s symptoms and medical history. Symptoms of dry or irritated eyes, dry skin, rash, and/or joint pain raise the possibility of Sjögren syndrome Sjögren Syndrome Sjögren syndrome is a common autoimmune connective tissue disorder and is characterized by excessive dryness of the eyes, mouth, and other mucous membranes. White blood cells can infiltrate... read more Sjögren Syndrome . Doctors also ask about a history of past or current radiation treatment, head and neck trauma, and a diagnosis of or risk factors for HIV infection. Doctors need to know all the medications a person is taking or substances being used to find out whether any are causing the dry mouth.

Doctors then do a physical examination. The physical examination is focused on the mouth, to see the degree of dryness. If the degree of dryness is unclear, doctors can hold a tongue depressor against the inside of the cheek for 10 seconds. If the tongue depressor falls off immediately when released, the flow of saliva is considered normal. If there is difficulty removing the tongue depressor, the flow of saliva is not normal. The lipstick sign, where lipstick sticks to the front teeth, may be a useful indicator of dry mouth.

Doctors also examine the mouth for the presence of any sores caused by the fungus Candida albicans and check the condition of the teeth (for instance, whether there are any cavities in unusual places). Unexpectedly severe and rapid tooth decay may be a sign of recreational and illicit drug use, particularly methamphetamines Amphetamines Amphetamines are stimulant drugs that are used to treat certain medical conditions but are also subject to abuse. Amphetamines increase alertness, enhance physical performance, and produce euphoria... read more .

What doctors find during the history and physical examination often suggests a cause of the dry mouth (see table ) and the tests that may need to be done. If the dry mouth began shortly after a new medication was started, doctors often try stopping the medication to see whether symptoms go away.



Sometimes, doctors test how well the salivary glands are functioning by measuring the flow of saliva (a test called sialometry). People chew paraffin or apply citric acid to the tongue to stimulate the flow of saliva, and then doctors collect the saliva. Measuring the flow of saliva can help doctors determine whether the dry mouth is getting better or worse.

Treatment of Dry Mouth

  • Treatment of the cause, including stopping causative medications when possible

  • Sometimes medications to increase saliva production

  • Saliva substitutes

  • Regular oral hygiene and dental care

When possible, the cause of dry mouth is treated. For people with medication-related dry mouth whose current medications cannot be stopped or changed, medications should be taken in the morning rather than at night, because nighttime dry mouth is more likely to cause cavities Cavities Cavities are decayed areas in the teeth, the result of a process that gradually dissolves a tooth’s hard outer surface (enamel) and progresses toward the interior. (See also Overview of Tooth... read more Cavities . For all medications, easy-to-take formulations, such as liquids, should be considered. Medications that need to be placed under the tongue should be avoided. People should drink water before swallowing capsules and tablets or before placing nitroglycerin under the tongue. People also should avoid decongestants and antihistamines.

Symptom control

Treatment that helps control the symptoms of dry mouth consists of measures that

  • Increase existing saliva

  • Replace saliva with other liquid

  • Control cavities

Medications that increase saliva production include cevimeline and pilocarpine. The main side effect of cevimeline is nausea. The main side effects of pilocarpine include sweating, flushing, and excreting large volumes of diluted urine (polyuria).

Sipping sugarless fluids frequently and chewing gum that contains xylitol helps stimulate saliva flow. Using an over-the-counter saliva substitute containing carboxymethylcellulose, hydroxyethylcellulose, or glycerin may also help.

Petroleum jelly can be applied to the lips and under dentures to relieve drying, cracking, soreness, and trauma of the lining of the mouth. A cold-air humidifier may aid mouth breathers, who typically have their worst symptoms at night.

Meticulous oral hygiene is essential. People should brush (using a commercial or prescription fluoride toothpaste) and floss regularly (including just before bedtime) and use fluoride rinses or gels daily. Newer toothpastes with added calcium and phosphates also may help prevent cavities. People should see their dentist more often for preventive dental care and plaque removal. The most effective way to prevent cavities is to use custom-fitted mouth trays filled with prescription toothpaste for at-home fluoride application, especially at night. People may prefer to apply prescription fluoride toothpaste to the teeth without using a tray. In addition, a dentist can apply a sodium fluoride varnish 2 to 4 times per year.

People should avoid sugary or acidic foods and beverages and any irritating foods that are dry, spicy, or excessively hot or cold. People should especially avoid sugar near bedtime.

Essentials for Older Adults: Dry Mouth

Dry mouth is more common among older adults, but this is probably due to the many medications typically used by older adults rather than to aging itself.

Key Points

  • Medications are the most common cause, but some diseases (most commonly Sjögren syndrome or HIV infection) and radiation therapy can also cause dry mouth.

  • Saliva flow can be increased by chewing gum that contains xylitol or sucking on sugarless candy, by taking certain medications, and by using artificial saliva replacement.

  • Because people with dry mouth are at high risk of tooth decay, meticulous oral hygiene, additional preventive measures at home (including daily use of over-the-counter fluoride rinses or dentist-prescribed fluoride toothpaste), and dentist-applied fluoride are essential.

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

  • Provides information on oral health, including nutrition and guidance on selecting products that carry the American Dental Association's seal of approval. There is also advice on finding a dentist and how and when to see one.

Drugs Mentioned In This Article

Generic Name Select Brand Names
Deponit, GONITRO , Minitran, Nitrek, Nitro Bid, Nitrodisc, Nitro-Dur, Nitrogard , Nitrol, Nitrolingual, NitroMist , Nitronal, Nitroquick, Nitrostat, Nitrotab, Nitro-Time, RECTIV, Transdermal-NTG, Tridil
Adsorbocarpine, Akarpine, Isopto Carpine, Ocu-Carpine, Pilocar, Pilopine HS, Salagen, Vuity
Colace Glycerin, Fleet, Fleet Pedia-Lax, HydroGel, Introl , Lubrin, Orajel Dry Mouth, Osmoglyn, Sani-Supp
ACT Anti Cavity Flouride, ACT Dry Mouth Anti Cavity with Xylitol, biotene Dry Mouth, biotene PBF Dry Mouth, Blank, Denta 5000 Plus, Dentagel, Dental Resources Neutral, Duraflor, Epiflur, EtheDent, Fluorabon, Fluor-A-Day, Fluorident , FLUORIDEX, Fluorinse, Fluorishield (Sodium Fluoride), Fluoritab, FluoroCare Neutral, Flura-Drops, Flura-Loz, Karigel, Karigel-N, Listerine Smart Rinse, Lozi Flur, Ludent, Luride, Morning Fresh, NaFrinse, Neutracare, Neutragard, Neutral, Neutral Floam, Neutral One Minute, Nice, Pediaflor, Perfect Choice Neutral, Pharmaflur , Phos-Flur, Plus Neutral, PreviDent, PreviDent 5000 Booster , PreviDent 5000 Booster Plus, PreviDent 5000 Dry Mouth, PreviDent 5000 ORTHO DEFENSE, PreviDent 5000 Plus, PreviDent Dental, Protect , ReNaf, SF 5000 Plus, SodiPhluor, Sultan/Topex Neutral Ph, Thera-Flur, Thera-Flur N, Wenthworth, Wentworth, Wentworth Sodium Fluoride, White Coral
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