Most canker sores heal on their own within about two weeks, but you can speed up that timeline and reduce pain significantly with the right approach. The key is starting treatment early, ideally at the first tingling sensation before the sore fully forms, and avoiding the foods and habits that slow healing.
What You’re Dealing With
Canker sores are small, shallow ulcers that form on the soft tissues inside your mouth: the inner cheeks, lips, tongue, or gums. They’re not contagious (unlike cold sores, which appear on the outside of your lips). Most are minor sores that hurt for a few days and fully heal within two weeks without scarring. Larger sores can linger for a month or more, and clusters of tiny sores can fuse together and persist even longer.
You’ll usually feel a burning or tingling sensation a day or two before the sore appears. Then a round or oval white or yellowish ulcer develops, often with a red border. Pain typically peaks in the first few days and gradually fades from there.
Saltwater and Baking Soda Rinses
The simplest home treatment is a saltwater rinse. Mix about half a teaspoon of table salt into a cup of warm water, swish it around your mouth for 30 seconds, and spit. Do this a few times a day, especially after meals. Salt draws fluid out of the inflamed tissue, which helps reduce swelling and creates a less hospitable environment for bacteria.
Baking soda works similarly. Dissolve a teaspoon in half a cup of warm water and use it as a rinse, or make a paste with a small amount of water and dab it directly on the sore. Baking soda neutralizes acids in your mouth that irritate the ulcer, which is why it can bring noticeable relief quickly.
Over-the-Counter Pain Relief
Numbing gels and pastes containing benzocaine (sold under names like Anbesol and Orabase) can be applied directly to the sore to temporarily block pain. These work best when you apply them right before eating so you can get through a meal without wincing. Reapply as directed on the packaging, typically every few hours.
Antiseptic mouth rinses containing hydrogen peroxide (like Orajel Antiseptic Mouth Sore Rinse) serve a dual purpose: they clean the ulcer and help prevent secondary infection, which can delay healing. These rinses sting briefly on contact but can shorten how long the sore sticks around. You can also dilute standard 3% hydrogen peroxide with equal parts water and dab it on with a cotton swab.
Protective pastes that form a barrier over the sore are another option. They shield the ulcer from friction and food contact, giving the tissue underneath a better chance to repair itself.
Honey as a Topical Treatment
Plain honey applied directly to a canker sore is more than a folk remedy. A clinical trial comparing honey to a standard prescription steroid paste found that honey reduced ulcer size and pain faster. The honey-treated group healed in an average of about 3 days, compared to nearly 6 days for the steroid group and 7 days for the control group. Dab a small amount of raw honey onto the sore a few times a day. It forms a protective coating and has natural anti-inflammatory properties. Expect it to sting briefly on application.
Foods to Avoid While Healing
What you eat can make a meaningful difference in how quickly your sore resolves. Acidic foods like oranges, grapefruit, pineapple, and coffee directly irritate the exposed tissue and can intensify pain for hours. Spicy foods do the same. Salty, crunchy items like chips and pretzels can physically scrape the sore and reopen it.
Less obvious triggers include strawberries, chocolate, cheese, and nuts, all of which bother some people. Stick to soft, bland foods while the sore is at its worst. Cool or room-temperature foods tend to be more comfortable than hot ones.
Preventing Future Outbreaks
If you get canker sores regularly, your toothpaste may be part of the problem. A systematic review of clinical trials found that switching to a toothpaste without sodium lauryl sulfate (SLS), a foaming agent in most toothpastes, significantly reduced the number of ulcers, the duration of each outbreak, and pain levels. SLS is thought to dry out and irritate the protective mucous layer inside your mouth. Brands like Sensodyne, Biotene, and several others make SLS-free options that are easy to find at most drugstores.
Nutritional deficiencies are another common contributor. Studies consistently find that people with recurrent canker sores are more likely to have low levels of vitamin B12, folate, and iron. One study found nutritional deficiencies in roughly 14 to 18 percent of canker sore patients screened. Correcting those deficiencies through diet or supplements often reduces how frequently sores return. Good dietary sources of B12 include meat, fish, eggs, and dairy. Folate is found in leafy greens, beans, and fortified grains. If you suspect a deficiency, a simple blood test can confirm it.
Beyond nutrition, pay attention to mechanical triggers. Braces, ill-fitting dentures, and even biting the inside of your cheek during sleep can set off new sores. Stress is another well-established trigger, though it’s harder to control.
When a Canker Sore Needs Medical Attention
A sore that hasn’t healed after two weeks, keeps coming back in frequent episodes, or is large enough to make eating and drinking genuinely difficult warrants a visit to your doctor or dentist. Prescription options include steroid-based pastes and rinses that reduce inflammation more aggressively than anything available over the counter. In some cases, a provider can chemically cauterize the sore to destroy the damaged tissue, which often brings immediate pain relief and jumpstarts healing. Sores accompanied by high fever, extreme fatigue, or spreading to the outer lips (which would suggest a different diagnosis) also deserve prompt evaluation.