Most mouth ulcers (canker sores) heal on their own within 10 to 14 days, but the right treatments can cut pain significantly and speed that timeline. The key is reducing irritation, managing pain with topical products, and creating conditions that let the tissue repair itself. Here’s what actually works.
Make Sure It’s a Mouth Ulcer
Mouth ulcers (canker sores) are painful white or yellow sores that form inside the mouth, on the inner cheeks, lips, or tongue. Cold sores, by contrast, appear outside the mouth, typically around the border of the lips, and are fluid-filled blisters caused by the herpes virus. The distinction matters because the treatments are completely different. If your sore is inside the mouth, you’re dealing with a canker sore, and the strategies below apply.
Rinses That Promote Healing
A saltwater or baking soda rinse is the simplest first step. Dissolve one teaspoon of baking soda in half a cup of warm water and swish gently for 30 to 60 seconds. You can also use a half teaspoon of table salt in the same amount of water. Either option helps clean the ulcer, reduce bacteria, and temporarily ease pain. Rinse three to four times a day, especially after meals.
For more stubborn ulcers, your dentist or doctor can prescribe a steroid mouthwash. These rinses reduce inflammation directly at the ulcer site. You swish, hold for about a minute, then spit it out. They’re typically used four times a day after meals and before bed, and you avoid eating or drinking for 30 minutes afterward so the medication stays in contact with the tissue.
Over-the-Counter Pain Relief
Topical gels containing benzocaine are the most widely available option at pharmacies. Apply a small amount directly to the ulcer as needed, up to four times a day. The numbing effect kicks in within a minute or two and lasts long enough to eat or drink more comfortably. These products work best when you dry the ulcer gently with a tissue before applying, so the gel sticks to the surface rather than washing away with saliva.
Protective pastes that form a barrier over the ulcer are another option. They won’t numb the area, but they shield the raw tissue from food, drinks, and your teeth, which prevents the repeated irritation that slows healing.
Honey as a Home Remedy
Applying honey directly to a mouth ulcer is one of the better-supported home remedies. A systematic review of studies on honey for oral ulcers found it relieved symptoms earlier than no treatment, reduced pain scores, and caused no adverse effects. In some comparisons, honey performed about as well as standard pharmacy gels for both pain and ulcer size. Use a small dab of raw honey on the ulcer a few times a day. It won’t work miracles overnight, but the anti-inflammatory and antimicrobial properties give healing a genuine nudge.
Chemical Cauterization
If you’ve ever wished you could just “burn off” a canker sore, that’s essentially what silver nitrate cauterization does. A dentist or doctor applies a silver nitrate stick to the ulcer, which triggers a chemical reaction that seals the exposed tissue and nerve endings. The result is rapid pain relief, often within minutes. The ulcer still needs time to heal underneath, but the intense soreness largely disappears. This is worth asking about if you get large or especially painful ulcers that interfere with eating or talking.
How Long Healing Takes
Minor canker sores, the kind most people get, heal within 10 to 14 days without scarring. Mild episodes in people who get occasional ulcers can resolve in as little as two to three days. Major aphthous ulcers, which are larger and deeper, can take up to six weeks to fully heal and sometimes leave scars. If your ulcers tend to be the larger variety, prescription treatments are worth pursuing rather than waiting it out.
Any mouth ulcer that hasn’t healed within two to three weeks deserves professional attention. An ulcer lasting longer than four weeks should be evaluated by a specialist promptly. Persistent sores that don’t respond to treatment need a biopsy to rule out more serious conditions, including oral cancer.
Prevent the Next One
If you get mouth ulcers repeatedly, the single most impactful change you can make is switching to a toothpaste free of sodium lauryl sulfate (SLS), the foaming agent in most commercial toothpastes. In a clinical study, people who switched to an SLS-free toothpaste experienced roughly 70% fewer ulcers compared to their baseline. Even compared to an SLS-containing toothpaste used in the same study, the reduction was about 60%. SLS-free options are available at most pharmacies and are usually labeled as such on the packaging.
Nutritional deficiencies also play a role in recurrent ulcers. Low levels of vitamin B12, folate, and iron are all clinically linked to repeated canker sores. If you’re getting ulcers several times a year, it’s worth having your levels checked through a simple blood test. Correcting a deficiency through diet or supplements can reduce how often ulcers come back.
Beyond those two strategies, pay attention to physical triggers. Biting the inside of your cheek, rough edges on braces or dental work, and hard-bristled toothbrushes all create the kind of tissue damage that invites ulcers. Acidic foods like citrus, tomatoes, and vinegar-based dressings can irritate existing sores and may trigger new ones in people who are prone to them. Stress is another well-established trigger, which helps explain why ulcers tend to cluster around high-pressure periods at work or school.