Dry mouth: causes, medicines, Sjögren’s syndrome and what to do when saliva runs short

What is dry mouth, and how does xerostomia differ from a lack of saliva?

Dry mouth (xerostomia) is the subjective feeling that there is not enough saliva in the mouth, while reduced saliva secretion (hyposalivation) is a condition that can be measured. A 2015 review by Villa et al. states that hyposalivation is present when resting secretion is 0.1 ml per minute or less, and stimulated secretion, for example when chewing, 0.5 to 0.7 ml per minute or less.

For comparison, according to the same review normal resting secretion is about 0.3 to 0.4 ml per minute, and stimulated secretion averages 1.5 to 2.0 ml per minute. The authors of a 2026 meta-analysis (Kamnoedboon et al.) stress that xerostomia and hyposalivation are separate conditions, assessed by different methods, so a feeling of dryness does not always mean less saliva.

Dry mouth is common. A 2018 meta-analysis by Agostini et al., based on 29 population studies, estimated its prevalence at 22.0%, with higher figures in studies of older people. In the 2026 meta-analysis, covering 37 studies and more than 1.6 million people over the age of 50, a feeling of dryness affected 21% of participants and a measured shortage of saliva 12 or 13%, depending on the measurement method.

Where does dry mouth come from? Causes and clues

Dry mouth usually has one or several causes, which a dentist or doctor identifies by taking a history: the medicines you take, your habits, illnesses and past treatment. The NHS, the UK’s public health service, lists dehydration, medicines, breathing through the mouth at night, anxiety, radiotherapy or chemotherapy and oral thrush, and where the dryness does not go away, also diabetes and Sjögren’s syndrome.

According to a 2010 MASCC and ISOO systematic review (Jensen et al.), radiotherapy to the head and neck damages the salivary glands in proportion to the radiation dose, while dryness after chemotherapy is milder and temporary. The table brings together the causes named in these sources and the clues that help to recognise them.

Dry mouth and medicines: which medicines can dry the mouth?

Medicines are among the common causes of dry mouth: the US National Institute of Dental and Craniofacial Research (NIDCR) states that several hundred different medicines can reduce saliva secretion. A 2017 systematic review by Wolff et al., prepared as part of the World Workshop on Oral Medicine, identified 56 substances with stronger and 50 with moderate evidence of a link to salivary gland dysfunction, a subjective feeling of dryness or excessive salivation. It is therefore not simply a list of medicines that reduce the amount of saliva.

The medicines on this list act mainly on the digestive, cardiovascular, genitourinary, nervous and respiratory systems. They include, among others, antidepressants and antipsychotics, antihistamines, antiepileptics, medicines for high blood pressure, diuretics, medicines for an overactive bladder and some inhaled medicines.

In the 2026 meta-analysis by Srisanoi et al., polypharmacy (taking many medicines at once) in people aged 75 or over was associated with higher odds of dry mouth (odds ratio 2.05); this does not mean that dry mouth is twice as common, nor does it prove cause and effect. Wolff et al. name switching or stopping the medicine, where possible, as the first step, but the decision rests with the doctor, and the NHS warns against stopping prescribed treatment without advice.

Dry mouth at night: why is it worse in the morning?

Dry mouth at night and on waking in the morning often results from breathing through the mouth during sleep, for example with a blocked nose or when sleeping with the mouth open. This is how the NHS describes it, and it advises keeping water by the bed to sip in small amounts.

Before sleep, saliva secretion falls and saliva neutralises acids less effectively, which is why the UK guidance Delivering Better Oral Health advises avoiding sugary snacks and drinks at that time. If your nose is constantly blocked, it is worth having the cause investigated by your GP or an ENT specialist.

• Keep a glass or bottle of water by your bed.
• Use a humidifier in the bedroom, as the NIDCR recommends.
• Take your denture out at night; the NHS advises against sleeping in it.
• Have sugary food and drinks before your evening toothbrushing, not after it.

Sjögren’s syndrome: when is dry mouth a symptom of illness?

Sjögren’s syndrome is a disease in which the immune system attacks the glands that produce fluids, above all tears and saliva. The NHS lists dry eyes and a dry mouth as the main symptoms, along with muscle and joint pain and extreme tiredness; women are affected more often than men.

Primary Sjögren’s syndrome is a rare disease. A 2015 meta-analysis by Qin et al. estimated its prevalence at about 61 cases per 100,000 people, with about 10 women affected for every man and an average patient age of 56.

Diagnosis requires tests ordered by a doctor, usually after referral to a specialist. The NHS lists blood tests, eye tests, measuring the amount of saliva, an X-ray of the salivary glands and a biopsy of the lip including minor salivary glands, and the 2016 ACR and EULAR classification criteria include, among other things, resting saliva secretion of 0.1 ml per minute or less.

For dry mouth, the 2019 EULAR recommendations include saliva substitutes and medicines that stimulate saliva secretion from the group of muscarinic receptor agonists, which are prescribed by a doctor. If, as well as a dry mouth, you have dry, burning eyes, tell your GP.

What does a lack of saliva mean for teeth, gums and dentures?

A lack of saliva increases the risk of tooth decay and fungal infections, because saliva washes away food debris, makes swallowing easier and contains minerals that strengthen the teeth. This is how the NIDCR explains it, and the NHS states plainly that decay is more likely with a dry mouth.

The 2015 review by Villa et al. also lists difficulty speaking, chewing and swallowing, poorer denture retention, changes in taste, bad breath and a burning sensation in the mouth. People with hyposalivation often tolerate spicy, acidic and crunchy foods poorly. Bad breath and denture care for older people are covered in separate articles.

The UK guidance Delivering Better Oral Health (updated 10 September 2025) classes adults whose medicines or cancer treatment cause dry mouth as being at increased risk. For this group it recommends a daily fluoride mouthwash (0.05% sodium fluoride), used at a different time from toothbrushing, and fluoride varnish applied twice a year. According to the American Dental Association (ADA), the 2.26% figure given for varnish refers to the fluoride ion content (22,600 ppm), which corresponds to 5% sodium fluoride.

With active decay of the crown or root, the same guidance allows a prescription toothpaste containing 2,800 or 5,000 ppm fluoride to be considered until the decay is under control. The dentist sets the interval between check-ups according to risk: the guidance gives a range of 3 to 24 months and recommends shortening it when the risk of decay is high.

Lack of saliva: what can you do day to day to ease the dryness?

Relieving dry mouth starts with removing the cause where possible, and the symptoms are eased with simple measures listed by the NHS. The 2021 ISOO, MASCC and ASCO guideline on dryness after cancer treatment regards mucosal moisturisers, saliva substitutes and sugar-free lozenges and chewing gum as helpful.

Pharmacies sell gels, sprays, tablets and lozenges that moisten the mouth and, for a blocked nose, decongestants; it is worth choosing a product together with a pharmacist or dentist. According to the review by Villa et al., chewing gum increases saliva secretion and reduces friction on the mucosa.

• Sip cold water throughout the day.
• Suck ice cubes or drink cool sugar-free drinks.
• Chew sugar-free gum or suck sugar-free lozenges.
• Brush your teeth twice a day with fluoride toothpaste and use an alcohol-free mouthwash.
• Cut down on alcohol, caffeine (coffee and tea) and fizzy drinks.
• Avoid acidic, spicy, salty and sugary foods.
• Do not smoke.
• For dry lips, use a lip balm.
• If you have your own teeth, do not use acidic artificial saliva products.

When should you see a doctor or dentist about dry mouth?

It is worth seeing your GP about dry mouth if it has not gone away after a few weeks of home remedies and pharmacy products, and sooner if other symptoms come with it. The NHS lists the situations gathered below, and a dentist will check the condition of your teeth, gums and mucosa at the same time.

• The dryness makes it hard to speak or eat, or you find it difficult to eat regularly.
• Your mouth is still dry after a few weeks of home remedies and pharmacy products.
• Changes in taste do not go away.
• Your mouth is painful, red, swollen or bleeding.
• Painful white patches have appeared in your mouth.
• You suspect that a prescribed medicine is causing the dryness.
• You also have other symptoms, such as passing urine often or dry eyes.

How it works at DentalBlue

At DentalBlue in Białystok, the starting point for dry mouth is an examination of the teeth, gums and mucosa and a conversation about the medicines you take. The “Wizyta bez bólu” (visit without pain) includes a panoramic X-ray, a consultation, an examination and a written treatment plan, and costs 300 zł in the clinic’s price list. The clinic provides preventive care and professional cleaning; the item “Fluoryzacja” (fluoride treatment) costs 100 zł in the price list. The final scope and cost are set at the visit, and prices may change. General illnesses such as Sjögren’s syndrome or diabetes are diagnosed by a GP or a specialist.