Most canker sores heal on their own within one to two weeks, but the right combination of pain relief, rinses, and trigger avoidance can cut down on discomfort and may speed recovery. What works best depends on how severe your sore is and whether you’re dealing with occasional flare-ups or a recurring pattern.
Topical Numbing Gels for Immediate Pain Relief
Over-the-counter gels containing benzocaine are the most widely available option for quick relief. Benzocaine is a local anesthetic that numbs the tissue on contact, temporarily blocking pain signals from the sore. You apply it directly to the ulcer, and within minutes the area goes numb. The tradeoff is that you need to be careful not to chew on your cheek or tongue while the numbness lasts. Products with lidocaine work similarly. These gels don’t accelerate healing, but they make eating and talking far more tolerable.
Protective pastes that form a barrier over the sore serve a different purpose. They shield the raw tissue from contact with food, drinks, and your teeth, which reduces irritation throughout the day. Some products combine a numbing agent with this protective coating.
Saltwater and Medicated Rinses
A simple saltwater rinse is one of the oldest and most accessible remedies. Dissolve about half a teaspoon of salt in a cup of warm water, swish for 30 seconds, and spit. This draws fluid from swollen tissue and keeps the area cleaner, which can ease pain and support healing. You can repeat this several times a day, especially after meals.
Baking soda rinses work on a similar principle, helping to neutralize acids in the mouth that irritate the sore. For more persistent or painful ulcers, prescription rinses are available. These include formulations containing anti-inflammatory steroids or antimicrobial agents that reduce swelling and bacterial activity around the ulcer. Some dentists prescribe what’s informally called “magic mouthwash,” a compounded rinse that typically combines a numbing agent, an anti-inflammatory, and sometimes an antifungal.
Prescription Options for Severe Sores
When over-the-counter products aren’t enough, a dentist or doctor can prescribe a steroid dental paste. Triamcinolone paste, sold under brand names like Kenalog in Orabase, is applied directly to the ulcer. It works by reducing inflammation in the tissue, which relieves pain and can help the sore resolve faster. You press a small amount onto the ulcer, usually at bedtime, and the paste adheres to the moist tissue.
For especially stubborn or large sores, cauterizing agents are another option. These are applied in a clinical setting and chemically seal the ulcer surface, which can dramatically reduce pain almost immediately and shorten healing time. This approach is typically reserved for sores that are unusually large or haven’t responded to other treatments.
Honey as a Topical Treatment
Applying honey directly to a canker sore is a home remedy with some clinical backing. A systematic review of studies on honey for oral ulcers found that when participants applied honey three times daily for five days, improvements in both pain and ulcer size were comparable to those seen with standard medicated gels. No significant difference was found between the honey group and the medication group for either pain scores or ulcer size. No adverse effects were reported. Raw, unprocessed honey applied with a clean finger or cotton swab is the typical approach. It coats the sore and has natural antimicrobial and anti-inflammatory properties.
Foods and Habits That Make Sores Worse
Acidic foods like citrus fruits, tomatoes, and vinegar-based dressings can sting badly on contact and may slow healing by repeatedly irritating the exposed tissue. Spicy foods, salty snacks like chips or pretzels, and anything with rough or sharp edges (think crusty bread, tortilla chips) can physically scrape the sore and trigger fresh waves of pain. While you have an active ulcer, sticking to softer, blander foods makes a noticeable difference in day-to-day comfort.
Your toothpaste may also play a role. Sodium lauryl sulfate, the foaming agent in most toothpastes, has been linked to canker sore outbreaks in multiple studies. In one clinical trial, 90 participants used two different toothpastes for eight weeks each. Those who used the SLS-free toothpaste reported that their canker sores didn’t last as long and caused less pain. If you get canker sores frequently, switching to an SLS-free toothpaste is one of the simplest changes you can make. Brands marketed for sensitive mouths often leave out SLS.
Vitamin B12 and Nutritional Gaps
Recurring canker sores are sometimes tied to nutritional deficiencies, particularly low levels of vitamin B12, folate, and iron. In a study of patients who averaged 1.5 canker sore episodes per month, daily sublingual vitamin B12 supplements (1,000 mcg) dropped that frequency to just 0.1 episodes per month. Notably, the improvement occurred regardless of whether participants had low B12 levels in their blood to begin with, suggesting the vitamin may have a protective effect on oral tissue beyond simply correcting a deficiency.
If you deal with canker sores more than a few times a year, it’s worth looking at your diet. Foods rich in B12 include meat, fish, eggs, and dairy. Folate comes from leafy greens, beans, and fortified grains. Iron is found in red meat, lentils, and spinach. A simple blood test can confirm whether a deficiency is contributing to the pattern.
When a Canker Sore Needs Attention
Most canker sores are small, round, and painful but harmless. A sore that hasn’t healed after two weeks warrants a visit to a dentist or doctor. Other signs that set a sore apart from a routine canker sore include red, white, or mottled patches in the mouth, a lump or bump beneath the surface of the ulcer, or symptoms that are getting worse rather than gradually improving. These features don’t necessarily mean something serious, but they overlap with early signs of oral conditions that benefit from early evaluation, including oral cancer. A quick in-office exam, and sometimes a biopsy, is all it takes to rule out anything concerning.