Most canker sores heal on their own within 10 to 14 days, but the right combination of topical treatments and home care can cut pain dramatically in the first 24 to 48 hours and support faster healing. The key is acting early: treatments work best when applied at the first sign of a sore, before it fully develops.
What You’re Dealing With
About 80% of canker sores are the minor type, smaller than 5 millimeters across, with a grayish-white center and a red border. These show up on soft tissue inside the lips, cheeks, or along the tongue and resolve within two weeks without scarring. The remaining cases are either major sores (larger than 1 centimeter, lasting up to six weeks, sometimes scarring) or herpetiform sores, which start as clusters of tiny ulcers that merge into one irregular, painful patch.
Knowing which type you have sets realistic expectations. For minor sores, you can meaningfully speed things up at home. For major or unusually persistent sores, you may need a prescription or in-office treatment.
Over-the-Counter Products That Help
The fastest relief comes from topical products applied directly to the sore. Look for one of these active ingredients:
- Benzocaine gels or pastes (sold as Anbesol, Orabase, Zilactin-B) numb the area on contact. They’re best for getting through meals or managing pain spikes throughout the day. Reapply as directed, since the numbing effect wears off.
- Hydrogen peroxide rinses (such as Orajel Antiseptic Mouth Sore Rinse or Peroxyl) clean the sore and reduce bacteria around it. These are useful as a first step before applying a gel or paste.
The critical detail is timing. Apply these products as soon as you notice a sore forming, not after it’s been painful for three days. Early application is consistently linked to shorter, less painful episodes.
Homemade Rinses Worth Trying
A simple saltwater-and-baking-soda rinse is one of the most widely recommended home treatments. Mix one teaspoon of baking soda and one teaspoon of salt into four cups (one liter) of water. Swish and spit several times after brushing, after eating, and whenever the sore feels irritated. Make a fresh batch every day.
This rinse does two things: the salt draws fluid from inflamed tissue, reducing swelling, while the baking soda creates a mildly alkaline environment that’s less hospitable to bacteria. It won’t numb pain the way benzocaine does, but it keeps the area clean and can prevent the sore from worsening.
Honey as a Topical Treatment
Applying a small amount of honey directly to a canker sore is more than folk medicine. A systematic review of studies on honey for oral ulcers found that it performed comparably to standard pharmacy gels for reducing pain and ulcer size in minor canker sores. In some studies on more severe oral ulcers, honey produced the fastest healing times of any group tested.
If you try this, use plain, unprocessed honey. Dab a small amount on the sore a few times a day, ideally after rinsing your mouth. It forms a protective coating and has natural antibacterial properties. The downside is that it doesn’t stay in place as well as a pharmacy paste, so you may need to reapply frequently.
In-Office Treatments for Stubborn Sores
If a canker sore isn’t responding to home care after several days, a dentist or doctor can use chemical cauterization to accelerate healing. Two options stand out in clinical research:
Silver nitrate, applied directly to the sore, was associated with more patients being pain-free by day one compared to placebo in a trial of 97 people. The trade-off: it didn’t actually shorten total healing time, so it’s primarily a pain solution.
Debacterol, a prescription topical agent, reduced pain significantly more than placebo by day three and resolved symptoms more effectively by day six. For a sore that’s making it hard to eat or talk, this can be a worthwhile option.
Your doctor may also prescribe a steroid-based topical like fluocinonide to reduce inflammation, particularly if you get canker sores frequently.
Foods to Avoid While You Heal
Nothing slows down healing like re-injuring the sore every time you eat. While a canker sore is active, steer clear of anything that creates a sharp or acidic sting on contact: chips, crackers, crusty bread, citrus fruits, tomato-based sauces, vinegar, and heavily spiced foods. Even hot beverages can aggravate the tissue.
Some people with recurrent canker sores notice that specific foods seem to trigger new outbreaks. Chocolate, peanuts, and eggs have been flagged as potential triggers in people with food sensitivities, though no studies have confirmed a direct cause-and-effect relationship. If you notice a pattern with a particular food, avoiding it is a reasonable experiment.
Nutritional Deficiencies That Fuel Recurrence
If you get canker sores repeatedly, a nutritional gap may be part of the picture. In one study comparing people with recurrent oral ulcers to healthy controls, over half of the ulcer group had low vitamin B12 levels, compared to zero in the control group. That’s a striking difference.
Iron and folate deficiencies are also associated with recurrent sores, though the link is less dramatic than with B12. If canker sores keep coming back every few weeks or months, it’s worth asking for a blood test to check these levels. Correcting a deficiency won’t heal the sore you have right now, but it can reduce how often new ones appear.
The SLS Toothpaste Question
You’ll find plenty of advice online to switch to a toothpaste free of sodium lauryl sulfate, the foaming agent in most commercial toothpastes. The theory is that SLS irritates the soft tissue inside your mouth and makes canker sores more likely. In practice, the evidence is thin. A 2019 review found there wasn’t enough data to conclude that SLS-free toothpastes reduced ulcer frequency, duration, or pain. A controlled study found no significant change in ulcer patterns after switching.
That said, SLS-free toothpastes are inexpensive and widely available. If your mouth generally feels irritated after brushing, trying one for a few months costs you nothing and might help. Just don’t expect it to be a cure.
A Practical Healing Plan
For the fastest possible recovery, layer your approach. Rinse with the salt-and-baking-soda solution after every meal. Apply a benzocaine gel or honey to the sore three to four times a day, especially before eating. Avoid crunchy, acidic, and spicy foods until the sore closes. If pain is severe and nothing is working after a few days, ask about Debacterol or silver nitrate cauterization.
Canker sores that last longer than three weeks, that are unusually large, that come with a fever, or that make it nearly impossible to drink fluids are worth getting evaluated. These patterns can signal a major aphthous ulcer or an underlying condition that needs attention beyond over-the-counter care.