Can mouth breathing cause tonsil stones, swollen tonsils or canker sores?

We found no study showing that mouth breathing directly causes tonsil stones, swollen tonsils or canker sores. What is well established is that breathing through your mouth at night dries it out, and a dry mouth loses some of saliva's protection against germs and sores. So a link is plausible, especially for tonsil stones, but it hasn't been proven. With swollen tonsils, the cause usually runs the other way.

What does mouth breathing do to your mouth?

It dries it out. The NHS lists breathing through your mouth at night as one of the main causes of dry mouth, whether that's from a blocked nose or simply sleeping with your mouth open.

Saliva does more than keep your mouth comfortable. The National Institute of Dental and Craniofacial Research (NIDCR) says it helps keep harmful germs in check, and that a dry mouth raises the risk of tooth decay and fungal infections. Its list of dry mouth symptoms includes mouth sores, repeated infections of the mouth or throat, and bad breath.

That's the reasonable basis for the questions in this article. The research we could find doesn't go further and test mouth breathing against tonsil stones or canker sores directly. Our article on the effects of mouth breathing at night covers what has been studied.

Can mouth breathing cause tonsil stones?

Possibly, but no one has shown it. Cleveland Clinic explains that tonsil stones are small lumps of hardened material, made of minerals such as calcium, food debris and bacteria or fungi. They form when debris gets trapped in folds of the tonsils called tonsillar crypts and then hardens.

The risk factors Cleveland Clinic lists are frequent tonsil infections, enlarged tonsillar crypts, being a teenager and dehydration. Mouth breathing isn't on the list. A dry mouth from mouth breathing overlaps with the dehydration point, and its prevention tips include staying hydrated, brushing and flossing, brushing your tongue, gargling with salt water after eating and not smoking.

Tonsil stones are also very common. A 2013 study in BMC Oral Health reviewed 482 CT scans and found tonsil stones in 46.1% of them, with higher rates in people over 40. Cleveland Clinic says many people have them and don't know it, and that they're rarely harmful.

How do you get rid of tonsil stones?

Often you don't need to. Cleveland Clinic says tonsil stones commonly fall out on their own, and that swallowing one won't hurt you. If they bother you, it suggests gargling with warm salt water, coughing firmly to dislodge them, using a water pick to flush them out, or pushing them out gently with a cotton swab.

If home care doesn't work, a provider can remove them in the office. For stones that keep coming back or cause ongoing symptoms, Cleveland Clinic says a doctor may discuss removing the tonsils.

Why do tonsil stones cause bad breath?

Because of what they're made of. Cleveland Clinic names bad breath as the most common symptom, along with a bad taste, a sore throat, coughing and a feeling that something is stuck in your throat.

A 2008 study in the British Dental Journal measured the sulphur compounds behind bad breath in 49 people with chronic tonsil problems. A tonsil stone was present in 75% of those with abnormal results and in only 6% of those with normal results.

Mouth breathing causes bad breath too, through dryness. If you have both, it can be hard to tell which is to blame. Does mouth breathing cause bad breath? explains the dry mouth side.

Can mouth breathing make your tonsils swollen?

We found no good evidence that it does. The well-documented link runs the other way. Cleveland Clinic lists enlarged or infected tonsils and adenoids as a cause of mouth breathing, mainly in children, because they can block the airway.

That matters for adults too. If your tonsils are large, they may be part of the reason you breathe through your mouth, not a result of it. Tonsils that stay swollen, hurt, or come with fever or trouble swallowing need a doctor, not a home fix.

Can mouth breathing cause canker sores?

It isn't a recognised cause. Cleveland Clinic says experts aren't sure what causes canker sores, and lists possible causes and triggers including mouth injuries, stress, hormone changes, certain foods, toothpastes with sodium lauryl sulfate, vitamin and mineral deficiencies, and some medicines. The NHS list of mouth ulcer causes is similar, and neither mentions mouth breathing.

There is one indirect thread. The NIDCR lists mouth sores among the symptoms of dry mouth. So if you wake with a parched mouth most days and also get sores, it's reasonable to deal with the dryness, while knowing the research hasn't tied the two together.

Cleveland Clinic says most canker sores heal within two weeks. The NHS says to see a dentist or GP if an ulcer lasts longer than three weeks, because a long-lasting ulcer is sometimes a sign of something more serious.

What helps if you wake with a dry mouth?

Getting air back through your nose is the most direct fix for mouth breathing. Start by checking your nose with our two-minute nose test. If it feels blocked, clear it first. How to unblock your nose before bed has practical steps.

If your nose is clear and your mouth still falls open, mouth tape keeps your lips together through the night. The Sleep Foundation describes it as a gentle reminder that promotes nasal breathing. Research on tape is still limited, and it hasn't been studied for tonsil stones or canker sores, so think of it as a way to stop the dryness, not a treatment for either. Mouth tape for dry mouth goes into the details.

Cleveland Clinic advises against mouth taping if you have enlarged tonsils, nasal congestion, chronic allergies, a sinus infection or a deviated septum. Skip it on children, and see a doctor first if you snore loudly or might have sleep apnea.

If you'd like to try it, our pick is Titan Bamboo Silk Mouth Tape. Titan says it's a breathable bamboo silk strip with no ink on the side that touches your skin, and suggests 20 to 30 minutes of daytime practice before the first night.

When should you see a doctor?

Cleveland Clinic suggests talking to a provider if tonsil stones keep coming back, bother you, or don't clear with home care such as gargling. See a doctor too for tonsils that stay swollen, mouth sores that last more than two to three weeks, or a dry mouth that doesn't improve once you're breathing through your nose. The NHS notes that a dry mouth that won't go away can come from medicines or conditions such as diabetes.

Read next

• Why do I wake up with a dry mouth?
• Mouth breathing and your teeth
• What is mouth breathing?

* This content is for informational and educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure or prevent any disease or health condition. Talk to a qualified healthcare provider about your health.