Most minor canker sores heal on their own in 4 to 14 days, but the right treatment can cut that timeline dramatically. A mucoadhesive patch, for example, can resolve a sore in as little as 24 hours. The key is matching the treatment to the severity of your sore and starting as early as possible.
Mucoadhesive Patches: The Fastest Option
If speed is your priority, medicated patches that stick directly to the sore deliver the most impressive results. In a clinical comparison, sores treated with a mucoadhesive patch resolved in a median of 24 hours, compared to 120 hours (five days) for a medicated oral rinse. The patch works on two levels: it physically shields the sore from food, saliva, and friction while holding an active ingredient directly against the tissue. You can find these over the counter at most pharmacies, often sold under names like Cankermelts or similar adhesive disc products.
The catch is that patches work best on sores in accessible spots, like the inside of your lip or the front of your gums. A sore on the back of your tongue or deep in your throat is harder to patch.
Protective Coatings and Numbing Gels
Over-the-counter treatments generally fall into two categories: protective barriers and numbing agents. Protective coatings (sometimes called occlusives) form a film over the sore that blocks irritation from food, temperature changes, and mechanical contact. This shielding effect lets the tissue underneath heal without constant disruption. Products that combine a protective coating with a therapeutic ingredient give you both pain relief and a faster healing environment.
Numbing gels containing benzocaine reduce pain on contact but don’t actively speed up tissue repair on their own. They’re most useful when a sore is so painful that it’s interfering with eating or talking. For the best results, look for products that pair a numbing agent with a barrier or anti-inflammatory component rather than relying on numbing alone.
Honey as a Topical Treatment
Plain honey, applied directly to a canker sore, performs surprisingly well. A randomized controlled trial comparing honey to a topical corticosteroid and a plain protective paste found that honey significantly outperformed both in reducing sore size, pain, and redness. No side effects were reported in any group. The anti-inflammatory and antimicrobial properties of honey appear to create favorable conditions for tissue repair.
To use this approach, dab a small amount of raw honey directly on the sore a few times a day, especially after meals. Medical-grade honey is ideal, but regular raw honey works too. Avoid processed honey, which has lost most of its beneficial compounds.
Saltwater Rinses
A warm saltwater rinse is the simplest home remedy and genuinely helpful. Dissolve 1 teaspoon of salt in 1 cup of warm water and swish for 30 to 60 seconds. The saline solution reduces bacteria around the sore, draws out excess fluid from inflamed tissue, and creates a cleaner environment for healing. It won’t resolve a sore overnight, but it’s a solid supporting measure you can use several times a day alongside other treatments.
Laser Treatment at the Dentist
For stubborn or frequently recurring sores, dental laser therapy is the most aggressive option. In a clinical study using a low-level diode laser, all treated sores healed completely within six days, while untreated sores in the control group mostly showed moderate improvement or none at all. Pain and functional problems (difficulty eating, speaking) dropped noticeably within the first two days after treatment. A single session typically takes just a few minutes, and many patients report immediate pain relief.
This isn’t something you’d pursue for a one-off sore, but if you’re dealing with large, painful, or frequently recurring ulcers, it’s worth asking your dentist about.
Vitamin B12 for Recurring Sores
If canker sores are a regular part of your life rather than an occasional nuisance, a vitamin B12 deficiency may be playing a role. A randomized, placebo-controlled trial found that taking 1,000 micrograms of sublingual B12 daily for six months led to significant reductions in the number of sores, the duration of outbreaks, and pain levels. These improvements appeared around the five- to six-month mark, and they held regardless of whether participants had low B12 levels at the start of the study.
This is a long-term prevention strategy rather than a quick fix for a sore you already have. But for people who get canker sores monthly or more, it can meaningfully reduce how often they appear and how long each one lasts.
Switching Your Toothpaste
One surprisingly effective prevention step is switching to a toothpaste that doesn’t contain sodium lauryl sulfate (SLS), a foaming agent in most commercial toothpastes. In a study of people with frequent canker sores, switching to an SLS-free toothpaste reduced the average number of ulcers from about 14 to about 5 over the same time period. That’s roughly a 64% reduction just from changing toothpaste. Brands like Sensodyne, Biotene, and several others make SLS-free options that are easy to find.
Minor Versus Major Canker Sores
The treatments above work best for minor canker sores, which are smaller than 1 centimeter (usually 2 to 5 millimeters) and make up the vast majority of cases. Major canker sores, typically 1 to 3 centimeters across, are deeply set and can last anywhere from 10 days to 6 weeks. They often scar. If you have a sore that’s unusually large, hasn’t improved after two weeks, or keeps coming back in the same spot, that’s a different situation that may need prescription treatment.
Canker Sores Versus Cold Sores
Before treating a sore, make sure you’re treating the right thing. Canker sores appear inside the mouth as single, round, white or yellow sores with a red border. Cold sores (fever blisters) appear outside the mouth, usually around the lip border, as clusters of small fluid-filled blisters. They have completely different causes and treatments. Cold sores are caused by the herpes simplex virus and respond to antiviral medication, while canker sores are not contagious and are treated with the approaches described above.