Most canker sores heal on their own within one to two weeks, but the right combination of home care and over-the-counter treatments can cut down pain and speed that timeline. These small, round ulcers appear inside the mouth with a white or yellow center and a red border. Unlike cold sores, they aren’t contagious and never form on the outside of your lips.
Start With a Salt Water or Baking Soda Rinse
The simplest first step is a rinse you can make right now. Dissolve about half a teaspoon of salt (or baking soda) in a cup of warm water, swish it around your mouth for 15 to 30 seconds, and spit. Doing this a few times a day helps draw fluid out of the swollen tissue, creates a less hospitable environment for bacteria, and keeps the area clean so your body can repair the lining faster. It will sting for a moment, but many people notice relief within minutes afterward.
Over-the-Counter Numbing Gels
Benzocaine gels (sold as Orajel and similar brands) are the most widely available option at pharmacies. You apply a small amount directly to the sore, and the area goes numb within a minute or two. Use it up to four times a day, ideally before meals so eating is less painful. The numbing effect is temporary, lasting roughly 30 to 60 minutes, but it makes the worst days manageable.
Protective pastes that form a barrier over the sore are another option. These stick to the wet tissue inside your mouth and shield the ulcer from food, drinks, and your teeth rubbing against it. Look for products labeled as oral wound care or canker sore patches in the dental aisle.
Honey as a Topical Treatment
Applying a dab of honey directly to the sore several times a day is one of the better-studied natural remedies. Research on oral ulcers caused by cancer treatments found that honey reduced the development of moderate-to-severe mouth inflammation by 75% compared to standard care. While canker sores aren’t identical to treatment-induced ulcers, honey has well-documented anti-inflammatory and antimicrobial properties that appear to help oral tissue heal. Manuka honey is often recommended, but regular raw honey works too. Just apply a small amount with a clean finger or cotton swab and try not to eat or drink for a few minutes afterward.
Medicated Mouth Rinses
If your canker sores are large or especially painful, an antiseptic mouthwash containing chlorhexidine can reduce the severity and pain of the ulcer, though it won’t prevent future ones from forming. These rinses are available over the counter in many countries or by prescription depending on where you live. They work by keeping bacterial levels low around the wound, which lets your immune system focus on repair rather than fighting off infection at the sore site.
When a Dentist Can Help Faster
For a canker sore that’s making it hard to eat or talk, a dentist or doctor can apply a chemical cauterizing agent called Debacterol directly to the ulcer. This essentially seals the sore in a single office visit and can reduce healing time to about a week. Silver nitrate is another in-office option. It hasn’t been shown to speed healing, but it does relieve pain quickly by destroying the exposed nerve endings on the surface of the ulcer. Both procedures take only a few seconds and are typically done without anesthesia.
Preventing Canker Sores From Coming Back
Switch to SLS-Free Toothpaste
Sodium lauryl sulfate (SLS) is a foaming agent in most toothpastes, and it’s a well-documented trigger for recurrent canker sores. A systematic review pooling data from multiple clinical trials found that people who switched to SLS-free toothpaste developed significantly fewer ulcers than those using standard formulas. The reduction was consistent across every measure the researchers tracked: fewer sores, smaller sores, and less pain. Brands like Sensodyne, Biotene, and Verve all make SLS-free options that are easy to find.
Check for Nutritional Gaps
Recurrent canker sores are linked to deficiencies in vitamin B12, folate, and iron. B12 levels below 200 pg/mL are considered deficient, with levels between 200 and 300 pg/mL falling into a gray zone that warrants further testing. Folate deficiency is diagnosed when serum levels drop below 3 ng/mL. If you get canker sores frequently, especially several times a year, ask your doctor to check these levels with a simple blood draw. Correcting even a borderline deficiency sometimes reduces or eliminates outbreaks entirely.
Avoid Mechanical Triggers
Biting the inside of your cheek, aggressive brushing, and sharp edges on dental work are common physical triggers. If you notice sores consistently appearing in the same spot, a rough tooth edge or an ill-fitting retainer could be the culprit. Switching to a soft-bristled toothbrush and being gentler around the gums also helps reduce tissue irritation that sets the stage for ulcers.
Signs a Mouth Sore Needs Professional Attention
A typical canker sore, no matter how painful, resolves within two weeks. If yours hasn’t healed by then, it’s worth getting it looked at. The Cleveland Clinic identifies several red flags that distinguish a stubborn canker sore from something more serious: bleeding from the sore that persists beyond two weeks, any texture change on or around the ulcer (rough patches, cracking, crustiness, or a cottony feeling), and visible lumps or swelling in your neck, cheek, or jaw. None of these automatically mean cancer, but a sore that won’t heal is the single most common reason dentists recommend a closer look or biopsy.