You can’t make a canker sore disappear instantly, but the right combination of topical treatments and rinses can cut days off the healing process and significantly reduce pain in the meantime. Most minor canker sores heal on their own within 10 to 14 days. The goal of treatment is to protect the sore, relieve pain, and create conditions that let the tissue repair itself faster.
Rinses That Speed Healing
A simple salt water rinse is one of the fastest things you can do at home. Mix about half a teaspoon of salt into a cup of warm water, swish it around the sore for 30 seconds, and spit. This draws fluid out of the inflamed tissue, which reduces swelling and helps clean the area. You can repeat this several times a day, especially after meals.
Baking soda works similarly. Dissolve about a teaspoon in half a cup of warm water and use it as a rinse. Baking soda neutralizes acids in your mouth that irritate the open sore, creating a less hostile environment for healing. Some people alternate between salt water and baking soda rinses throughout the day.
Over-the-counter rinses containing hydrogen peroxide (like Peroxyl) serve double duty as antiseptics and mild cleansers. They help keep bacteria from colonizing the ulcer, which can slow healing. Dilute hydrogen peroxide to a 1:1 ratio with water if you’re using the standard 3% solution from a pharmacy, or follow the directions on a product designed for oral use.
Topical Treatments for Pain and Protection
Numbing gels and pastes containing benzocaine (sold under names like Anbesol, Orabase, and Zilactin-B) are the most widely available over-the-counter option. Applied directly to the sore, they create a temporary barrier that blocks pain and shields the ulcer from food and saliva. The key is applying them early. Products work best when you start using them as soon as the sore appears, before it fully develops.
Protective pastes that form a film over the sore are especially useful before meals. Press a small amount onto the ulcer with a clean finger or cotton swab and let it set into a smooth layer. Don’t rub it in, as the paste will crumble and lose its protective seal. Reapply after eating and before bed.
For natural alternatives, small clinical trials have found benefits from applying honey directly to canker sores. Honey has both anti-inflammatory and antimicrobial properties, and study participants saw reductions in ulcer size and pain compared to placebo. Deglycyrrhizinated licorice (DGL), available as dissolving patches or tablets you hold against the sore, has also shown promise in reducing pain and shrinking ulcers faster than doing nothing.
When You Need Something Stronger
If over-the-counter options aren’t enough, a dentist or doctor can offer more aggressive treatments. One option is chemical cauterization, where a solution is applied directly to the sore to destroy the damaged surface tissue and essentially reset the healing process. A product called Debacterol can reduce healing time to about a week even for serious sores. Silver nitrate is another cauterizing agent; it doesn’t necessarily speed healing, but it typically provides significant pain relief.
For frequent or severe outbreaks, prescription steroid pastes or rinses can reduce inflammation more effectively than anything available over the counter. A steroid dental paste is applied after meals and at bedtime by pressing a small amount onto the sore with a cotton swab to form a thin film. These are particularly useful for large ulcers or clusters of sores that make eating difficult.
How Long Healing Takes
Minor canker sores, the kind most people get, are usually less than a centimeter across. They heal within 10 to 14 days without scarring. Pain tends to be worst in the first few days and gradually fades as the surface tissue regenerates.
Major canker sores are larger than a centimeter, deeper, and significantly more painful. These can take up to six weeks to heal and may leave a scar. If you’re dealing with a sore this size, over-the-counter treatments alone are unlikely to be sufficient, and it’s worth getting professional treatment to manage pain and prevent complications.
Preventing the Next One
Canker sores tend to recur, so prevention matters as much as treatment. Nutritional deficiencies are one established trigger. Vitamin B12, iron, and folate deficiencies have all been linked to recurrent outbreaks. If you get canker sores frequently, it’s worth having your levels checked through a simple blood test. In documented cases, correcting a B12 deficiency resolved the pattern of recurring ulcers entirely.
Mechanical trauma is another common trigger. Biting your cheek, irritation from braces or dental appliances, and aggressive tooth brushing can all kick off a new sore. Using a soft-bristled toothbrush and being mindful of sharp foods (chips, crusty bread, hard candy) during an active outbreak helps avoid making things worse or starting a new sore nearby.
You may have heard that switching to a toothpaste without sodium lauryl sulfate (SLS), the foaming agent in most toothpastes, can prevent canker sores. The evidence here is weaker than many websites suggest. A 2019 review found insufficient data to conclude that SLS-free toothpastes reduce the frequency, duration, or pain of outbreaks. A controlled study found no significant change in ulcer patterns after switching. That said, some individuals do report fewer sores after making the switch, and SLS-free toothpaste won’t hurt, so it may be worth trying if you get sores often.
Signs a Sore Needs Professional Attention
A typical canker sore, while painful, follows a predictable pattern: it appears, hurts for a few days, and gradually heals. Certain signs suggest something else may be going on. Any mouth sore that lasts longer than two weeks without healing warrants a visit to a dentist or doctor. The same goes for a sore that bleeds persistently, a lump or thickening under the skin where the ulcer sits, or numbness in your tongue or other parts of your mouth.
Other red flags include red, white, or mottled patches in your mouth, visible swelling in your neck or jaw that persists beyond two weeks, unexplained voice changes, difficulty chewing or moving your tongue, and unintentional weight loss. These symptoms don’t necessarily mean something serious is wrong, but they overlap with signs of oral cancer and deserve evaluation. The distinguishing feature of a canker sore is that it heals. A sore that changes in appearance but doesn’t resolve is the one to take seriously.