General information only. This article explains dental topics in general terms and isn’t a substitute for personal advice. Everyone’s oral health and dental needs are different, so please see a dentist for advice that applies to you.
A dry mouth happens when the salivary glands do not make enough saliva. The medical term is xerostomia. Most people have a dry mouth now and then, for example when nervous or thirsty, but a mouth that stays dry can be uncomfortable and can affect the health of the teeth and gums.
Why saliva matters
Saliva does far more than keep the mouth moist. It washes away food and bacteria, neutralises the acids that cause decay and erosion, supplies minerals that help repair early damage to enamel, helps with tasting, chewing and swallowing, and protects the soft tissues of the mouth. When there is less saliva, all of these protective effects are reduced.
Signs of a dry mouth
- A sticky or dry feeling in the mouth, often worse at night or on waking.
- Thick or stringy saliva.
- Difficulty chewing, swallowing or speaking.
- A changed sense of taste.
- Cracked lips, or a dry, rough tongue.
- Bad breath.
- Dentures that feel loose or rub.
Common causes
- Medicines. This is the most common cause. Many medicines can reduce saliva, including some used for blood pressure, depression and anxiety, allergies, pain, and bladder problems. The effect is often greater when several medicines are taken together.
- Medical conditions such as diabetes, Sjögren’s syndrome (an autoimmune condition affecting the salivary and tear glands) and some other autoimmune conditions.
- Radiotherapy to the head and neck, and some types of chemotherapy.
- Dehydration, from not drinking enough, illness, exercise or hot weather.
- Mouth breathing, often due to a blocked nose or snoring, and some CPAP machines used for sleep apnoea.
- Alcohol, caffeine, smoking and vaping, which can all dry the mouth.
Dry mouth is more common in older adults, mainly because they are more likely to take medicines that cause it.
Effects on the teeth and gums
Without enough saliva, plaque and acids stay on the teeth for longer. This raises the risk of decay, particularly along the gum line and on exposed root surfaces, and decay can progress more quickly. A dry mouth can also make gum inflammation worse, increase the risk of fungal infections such as oral thrush, cause mouth ulcers and soreness, and make dentures harder to wear comfortably.
How dry mouth is managed
Management depends on the cause. It generally involves relieving the symptoms, for example with water, sugar-free gum or saliva substitutes, and protecting the teeth from decay, which may include extra fluoride and more frequent check-ups. If a medicine seems to be the cause, your doctor may be able to review it. Do not stop or change a medicine without speaking to your doctor first.
Common questions
Is a dry mouth just part of getting older?
Not in itself. Healthy older adults usually make enough saliva. Dry mouth is more common with age mainly because of medicines and medical conditions.
Why do I wake up with a dry mouth?
Saliva flow naturally drops during sleep. Breathing through the mouth, snoring, a blocked nose or a CPAP machine can make the mouth much drier overnight.
Can a dry mouth cause bad breath?
Yes. Saliva helps wash away the bacteria that produce odours, so a dry mouth is a common cause of bad breath.
When should I see a doctor?
See your doctor if a dry mouth persists, especially with dry eyes, joint pain, unexplained thirst or frequent urination, as these can point to an underlying condition that needs assessment.
When to see a dentist
If your mouth often feels dry, mention it at your next check-up, along with any medicines you take. A dentist can check for early decay and other effects and suggest ways to protect your teeth. More information: preventative dentistry.