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Canker Sores

Small, painful sores inside the mouth that aren’t contagious and usually heal on their own within a week or two. Knowing your triggers can mean fewer of them — and sores that keep coming back, or one that won’t heal, deserve a check with your dentist or doctor.

What are canker sores?

A canker sore is a painful, open sore inside the mouth. It is usually a single round white or yellow sore with a red border (NIDCR). The medical name is aphthous ulcer (MedlinePlus), and when they keep coming back doctors call it recurrent aphthous stomatitis (American Academy of Oral Medicine). They can be quite painful, but they aren’t contagious (MedlinePlus). They usually show up on the soft, moving parts of the mouth: the tongue, soft palate, cheeks and lips (American Academy of Oral Medicine), and sometimes on the gums (NIDCR). Some people feel burning or tingling in the area before a sore appears (NIDCR).

Three types

How common are they?

Very common. Recurrent canker sores are the most common condition of the lining of the mouth; a 2023 review puts the share of people affected at between 5% and 25%, peaking in the teens (review, Medicina Clínica). They often first appear in adolescence (American Academy of Oral Medicine), are most common around puberty, and happen less often after it (NIDCR). Some families get mouth ulcers more often (NHS). Most people have mild, infrequent sores, but people with severe disease may have frequent to almost constant outbreaks (American Academy of Oral Medicine).

What causes them?

Nobody knows exactly. Experts think the immune system plays a part (American Academy of Oral Medicine, American Dental Association), genes may make some people more prone (NHS), and a range of things can set a sore off, though reports vary (NIDCR). Common triggers include:

How long do they last?

Most canker sores go away on their own in one to two weeks, and treatment usually isn’t needed (NIDCR, NHS, American Dental Association). Major sores often last two weeks or more (American Academy of Oral Medicine).

Canker sore or cold sore?

They are often confused, but they are separate conditions with different causes (NIDCR, NHS):

When mouth ulcers keep coming back

Most canker sores are just canker sores. But frequent or unusual mouth ulcers can sometimes be a sign of something else, and the list of possible causes is long — from inherited fever syndromes to inflammatory bowel disease (review, Journal of Clinical and Aesthetic Dermatology). If your sores keep returning, a clinician may order tests, including blood tests, to look for a cause (American Academy of Oral Medicine, NIDCR). Conditions linked to mouth ulcers include:

See a dentist or doctor if:

Side by side

Six approaches compared

For every condition we look at the same six approaches: what each involves, what it typically costs, and what a patient can realistically expect.

ApproachWhat it involves Estimated costWhat to expect
Conventional medicine (AMA) Over-the-counter numbing gels, protective patches and pastes, and alcohol-free or antiseptic rinses; prescription steroid or chlorhexidine rinses and ointments; tests for an underlying cause when sores keep returning; laser or cautery for severe sores. At one pharmacy: a mouth-sore pain-relief gel about $6, a canker-sore patch pack about $10, a mouth-sore rinse about $12. A new-patient dental visit that includes an exam and X-rays commonly totaled about $150–$400 without insurance; a routine cleaning alone ran about $80–$200 (The Pricer, updated July 2026). Paying without insurance, many standard urgent care visits ran about $125–$300, with labs, X-rays or stitches adding to the bill (The Pricer, published July 2026). On Medicare you usually pay 20% of the approved amount after the Part B deductible (Medicare.gov). Treatment eases pain and may speed healing; most sores heal within two weeks either way. No benzocaine products for children under 2. Frequent sores deserve a look for a cause.
Chiropractic Being researched — coming soon.
Acupuncture Being researched — coming soon.
Herbal medicine Licorice (including dissolving patches and rinses), aloe vera gel, honey and chamomile applied in the mouth. At one pharmacy: an aloe-containing canker gel about $5. Small studies suggest licorice and aloe may ease pain or shrink sores; evidence for honey and chamomile is mixed. Licorice can interact with steroids. Never give honey to a baby under 1.
Massage therapy Being researched — coming soon.
MBHA Wellness Coach A soft toothbrush and gentle brushing, an SLS-free toothpaste trial, a trigger-food and stress diary, salt-water rinses, iron-, folate- and B12-rich meals, and tracking outbreaks to share with your clinician. Cost estimate being researched. Knowing your triggers may mean fewer and milder sores. A coach supports you; a coach never replaces a check for sores that won’t heal or keep coming back.

Approach 1 of 6

Conventional medicine (AMA)

Most canker sores go away without treatment (NIDCR). The aims of treatment are to ease the pain, help the sore heal faster and, where possible, cut down how often sores come back — no treatment yet does all three (American Academy of Oral Medicine). When sores keep coming back, it is also worth looking for a cause (NIDCR).

1. Over-the-counter relief

Benzocaine and young children. The FDA says over-the-counter mouth products containing benzocaine should not be used in children under 2 years old, under any circumstances, and should not be used for teething. Benzocaine can cause methemoglobinemia, a serious and sometimes fatal condition in which the blood carries much less oxygen. It can happen after a single use, even in someone who has used benzocaine before without trouble (FDA, FDA). Get medical help right away if anyone — child or adult — develops pale, gray or blue skin, shortness of breath, tiredness, headache, light-headedness or a racing heart after using it (FDA).

2. Prescription treatment

For severe, persistent or infected sores, a dentist or doctor may prescribe (NHS, American Academy of Oral Medicine):

3. Looking for a cause

If sores persist or keep returning, a clinician may check for other causes, sometimes with blood tests or a small sample (biopsy) of the sore (American Academy of Oral Medicine, NIDCR). If a blood test shows iron-deficiency anemia, iron tablets are usually recommended once the reason for it has been found (NHS); B12 or folate deficiency is also diagnosed with a blood test (NHS).

Who to see

Your dentist or primary care provider is a good first stop: a doctor can usually diagnose a canker sore by looking at it (NIDCR), and an ulcer that lasts more than 10 to 14 days should be checked by a dentist (American Academy of Oral Medicine). Your dental team also checks for signs of mouth cancer at each visit (American Dental Association).

What it costs

How well it works — what to expect

Expect relief rather than a quick fix: canker sores almost always heal on their own in one to two weeks, and treatment helps relieve the pain and speed up healing (NIDCR). A 2026 review of 41 earlier reviews found that steroids applied to the sore and low-level laser therapy consistently reduced pain and shortened healing time, but evidence that any treatment prevents sores from coming back is limited (umbrella review, Journal of Dermatological Treatment). There is no cure for recurring canker sores (NIDCR, American Academy of Oral Medicine).

Find a medical doctor in our directory

Approach 4 of 6

Herbal medicine

Several plant-based remedies have been tested on canker sores, mostly in small studies. They are worth discussing with your dentist or pharmacist, but none replaces a check-up when the warning signs above apply.

Licorice root

The U.S. National Center for Complementary and Integrative Health (NCCIH) says a licorice mouth rinse or gargle might reduce ulcer size and pain in people with recurring canker sores, while licorice applied to the sore might reduce ulcer size only — though overall there isn’t enough high-quality evidence to clearly support licorice for any condition (NCCIH).

  • In a 2008 U.S. trial, sores treated with a dissolving oral patch containing licorice root extract had shrunk significantly by day 8, while untreated sores had grown slightly. By day 4, 81% of the licorice-patch group reported no pain at rest, compared with 63% of the dummy-patch group and 40% of the untreated group. Each group had 23 people (trial, General Dentistry).
  • A 2023 review found six trials (314 people) of licorice pastes, patches and mouthwashes. The authors reported less pain, smaller sores and faster healing with no side effects, but the studies were too different to combine statistically (systematic review, Iranian Journal of Medical Sciences).

Safety: licorice contains glycyrrhizin, which can cause serious side effects, including irregular heartbeat, especially in large amounts or over a long time, and even small amounts have caused problems in people with high blood pressure or heart or kidney disease. “DGL” (deglycyrrhizinated licorice) products have the glycyrrhizin removed. Licorice applied to the skin may irritate, and licorice can interact with corticosteroids — worth knowing, since steroids are a common prescription for canker sores. Large amounts are unsafe in pregnancy (NCCIH).

Aloe vera

In a 2022 trial of 60 people aged 15 to 25 in Syria, an aloe vera gel shrank minor canker sores and eased pain more than a dummy gel by day 5, and did better than amlexanox, a medicated paste (trial, Cureus). That is a single small study. Aloe gel on the skin is generally well tolerated, with occasional burning, itching or rash; aloe taken by mouth is a different matter, with possible side effects, a possible interaction with the heart medicine digoxin, and safety concerns in pregnancy and breastfeeding (NCCIH).

Honey

A 2025 trial of 30 people in Egypt found that thyme honey on minor canker sores eased pain and shrank sores more than a standard steroid paste (trial, European Journal of Oral Sciences). A 2025 review that pooled trials found mixed results for honey compared with the steroid, and warned that there were few placebo-controlled trials and that the studies were at moderate to high risk of bias (systematic review, BMC Oral Health). Never give honey to a baby under 1 year old — it can carry bacteria that cause infant botulism, a very serious illness (NHS, MedlinePlus).

Chamomile

In a small 2006 study, most people using a chamomile extract on canker sores and other painful mouth ulcers rated its pain relief as excellent (study, Journal of Drugs in Dermatology). In a 2023 analysis of 43 trials of treatments applied to the sore, no treatment — chamomile included — clearly beat a placebo for pain, although chamomile ranked among the more promising (network meta-analysis, Journal of Oral Pathology and Medicine), and a 2025 review found chamomile did less well than a steroid paste (systematic review, BMC Oral Health). Chamomile can cause allergic reactions, more likely if you’re allergic to ragweed, chrysanthemums, marigolds or daisies, and it may interact with warfarin, some other medicines and birth control pills (NCCIH, NCCIH).

The bottom line

A 2026 review of the research found that herbal agents showed favorable short-term results with good safety (umbrella review, Journal of Dermatological Treatment), but most herbal studies are small. Tell your dentist, doctor and pharmacist about every herb or supplement you use, because some herbs and medicines interact in harmful ways (NCCIH). We don’t list strengths or doses here.

What it costs

GUM Canker-X gel, which contains aloe vera and coats the sore: about $5 (retail listing: Pasteur Pharmacy). Other herbal products: cost estimate being researched.

Approach 6 of 6

MBHA Wellness Coach

There is no sure way to prevent canker sores, but identifying and avoiding your own triggers can make flare-ups less frequent (NIDCR). An MBHA Wellness Coach can help you find yours and build gentler habits — alongside, never instead of, your dentist or doctor.

Gentle mouth care

Try an SLS-free toothpaste

The NHS advises against toothpaste containing sodium lauryl sulfate when you have mouth ulcers (NHS), and the American Academy of Oral Medicine notes that an SLS-free toothpaste reduces how often sores come back in some people (American Academy of Oral Medicine). The evidence is encouraging but limited: a 2019 review of four small crossover trials (124 people) found that SLS-free toothpaste reduced the number of ulcers, how long they lasted, how often they came and how much they hurt, while calling for better trials (systematic review, Journal of Oral Pathology and Medicine, commentary, Journal of Evidence-Based Dental Practice). Check the ingredient list, or ask your dentist to recommend a brand. A coach can help you run a fair trial: switch toothpaste and track whether your sores change.

Food and drink

  • While a sore heals, skip very spicy, salty or acidic foods, rough or crunchy foods such as toast or chips, and very hot or acidic drinks such as fruit juice. Softer foods and cool drinks through a straw are kinder (NHS). Hot, acidic or spicy foods can also trigger new sores (NIDCR).
  • Keep a simple food diary. Foods some people react to include wheat (gluten), nuts, tomatoes and various fruits, plus cinnamon and the preservative benzoic acid; trying a break from one suspected food at a time is a sound way to spot a trigger (American Academy of Oral Medicine). The aim is to notice your triggers and avoid those (NIDCR), not to cut out every food on the list.

Eating for iron, folate and vitamin B12

A healthy, balanced diet is part of the NHS self-care advice (NHS). If you get sores often, ask your provider about testing for nutritional deficiencies before taking supplements (NIDCR). Good food sources include:

  • Vitamin B12: meat, fish, milk, cheese, eggs and some fortified breakfast cereals. B12 isn’t found naturally in fruit, vegetables or grains, so vegans may not get enough (NHS). Stomach surgery, Crohn’s disease and some medicines, including proton pump inhibitors (PPIs) and metformin, can also lower B12 (NHS).
  • Folate: broccoli, Brussels sprouts, leafy greens such as cabbage, kale and spinach, peas, chickpeas and kidney beans, and breakfast cereals fortified with folic acid (NHS).
  • Iron: red meat, beans such as kidney beans, edamame and chickpeas, nuts, dried fruit such as apricots, and fortified breakfast cereals (NHS). If you are prescribed iron tablets, the NHS notes that drinking orange juice afterwards may help your body absorb the iron, while large amounts of tea, coffee and milk can make it harder (NHS).

Stress and rest

Stress and tiredness are common triggers (NHS, NIDCR). A coach can help you build a stress-reducing routine you’ll keep — especially around exams, deadlines or other busy times.

Track your outbreaks

Note when each sore appears, how big it is, how long it lasts, and what was going on — foods, toothpaste, stress, your menstrual cycle, a bitten cheek, a new medicine. Keeping an ulcer diary like this can reveal links to your diet, toothpaste or lifestyle, and sharing it with your dentist or doctor can help them plan treatment (American Academy of Oral Medicine). Frequent sores, or sores that come with other symptoms, are a reason to look for a cause (NIDCR, American Academy of Oral Medicine).

Still being researched: Chiropractic, Acupuncture, Massage therapy. We add each approach once its costs and results are sourced. Are you a practitioner with experience treating Canker Sores? Tell us.

In their own words

Wellness and lifestyle testimonials

Please read first. This is a personal experience, not medical advice. MBHA makes no medical claims and does not claim any product treats canker sores. See a clinician or dentist if a mouth sore lasts longer than about two weeks, is unusually large or painful, keeps coming back, or comes with a fever. Never fast or change what you take in order to treat mouth sores without medical advice.

My sister noticed that she stopped getting canker sores once she started sleeping under a far-infrared comforter.

— Name withheld

Shared with first names only. Lightly edited for length and spelling.

Member stories

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Sources

This page is for education only and is not medical advice. Costs are typical U.S. ranges and estimates; yours will depend on your provider, location and insurance. Talk with your doctor before starting, stopping or combining any treatment. In an emergency, call 911. See our disclaimer.

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