Most mouth ulcers heal on their own within one to two weeks, but you can speed up the process and reduce pain with simple home treatments, over-the-counter products, or, for stubborn cases, prescription options. The small round sores that appear inside your cheeks, lips, or on your tongue are called canker sores (aphthous ulcers), and they’re the most common type of mouth ulcer. Here’s what actually works to treat them and keep them from coming back.
Make Sure It’s a Canker Sore
Before treating a mouth ulcer, it helps to confirm what you’re dealing with. Canker sores appear inside the mouth and are usually single, round sores with a white or yellow center and a red border. They are not contagious and have no known viral cause, though they can be triggered by injury, stress, smoking, or nutritional deficiencies.
Cold sores (fever blisters) are a different thing entirely. They show up outside the mouth, typically around the border of the lips, and appear as clusters of small fluid-filled blisters caused by the herpes simplex virus. Cold sores require antiviral treatment, so the remedies below won’t help much with those. If your sore is inside your mouth and looks like a shallow crater, you’re likely dealing with a canker sore.
Salt Water and Baking Soda Rinses
A simple rinse is the easiest first step. Memorial Sloan Kettering Cancer Center recommends mixing 1 teaspoon of salt and 1 teaspoon of baking soda into 1 quart (4 cups) of water. Swish gently for 30 seconds and spit. You can do this several times a day, especially after meals. The salt helps draw out fluid from the inflamed tissue, and the baking soda creates a mildly alkaline environment that can soothe irritation and keep the area cleaner. This won’t dramatically speed healing, but it reduces discomfort and is safe to use as often as you like.
Over-the-Counter Pain Relief
For ulcers that make eating or talking painful, a topical numbing gel containing benzocaine is the most widely available option. You apply a small amount directly to the sore, and it temporarily deadens the nerve endings in that area. You can reapply as needed, but no more than four times a day. These gels, sprays, and ointments are available at most pharmacies without a prescription and work within minutes, though the relief typically lasts 30 to 60 minutes.
Antiseptic mouthwashes containing chlorhexidine can also help by keeping the ulcer clean and reducing the chance of a secondary bacterial infection, which can slow healing. If the ulcer is in a spot where you keep biting it, an over-the-counter oral adhesive patch can cover and protect the sore while it heals.
Honey as a Treatment
If you prefer a natural option, honey performs surprisingly well. A randomized clinical trial compared applying half a milliliter of honey three times a day to using a prescription steroid paste (triamcinolone acetonide) on the same schedule. Both groups saw about a 60% reduction in ulcer size within the first few days, and both reached complete healing by the final follow-up visit. Pain scores dropped at nearly identical rates: roughly 48% in both groups. The difference between the two treatments was not statistically significant, meaning honey matched the prescription paste for both pain relief and healing speed.
To try this, dab a small amount of plain, unprocessed honey directly onto the ulcer after meals and before bed. Let it sit without eating or drinking for a few minutes. It forms a natural protective coating and has anti-inflammatory and antimicrobial properties.
Prescription Options for Stubborn Ulcers
If a canker sore hasn’t improved after a week of home care, a prescription corticosteroid dental paste can help. The most common one is a steroid paste that you press onto the ulcer in a small dab (about a quarter inch) until a thin film develops. You don’t rub it in; it naturally forms a smooth, slippery coating over the sore. The best time to apply it is at bedtime so the medication stays in contact with the ulcer overnight. For more severe sores, you may need to apply it two or three times a day, ideally after meals.
If you don’t see meaningful improvement within seven days of using a prescription paste, that’s a signal to follow up with your dentist or doctor. If there’s still no progress after two weeks, further investigation is recommended to rule out other causes.
In-Office Treatments for Severe Pain
For ulcers that are extremely painful or keep recurring, a dentist can perform chemical cauterization using silver nitrate. This involves briefly touching the ulcer with a silver nitrate stick, which destroys the exposed nerve endings and seals the surface. In a controlled study, 60% of patients who received silver nitrate cauterization had fully healed ulcers by day seven, compared to 32% in the placebo group. The average healing time after the procedure was just 2.7 days, versus 5.5 days without it. Pain scores were significantly lower from the first day onward, and no side effects were recorded.
Laser treatment is another in-office option that works on the same principle: sealing the ulcer surface and reducing nerve sensitivity almost immediately. Both options are quick procedures that take only a minute or two.
Check for Nutritional Deficiencies
If you get mouth ulcers frequently, the cause may be nutritional rather than just bad luck. In a study of 273 patients with recurrent canker sores, about 20% had iron deficiency, 20% had some form of anemia, nearly 5% were low in vitamin B12, and about 3% were deficient in folic acid. These numbers are high enough that checking your blood levels is worthwhile if ulcers keep returning every few weeks.
Iron, B12, and folate all play roles in maintaining the lining of your mouth. When levels drop, that tissue becomes more fragile and slower to repair. A simple blood test can identify whether a deficiency is contributing to your ulcers, and supplementation or dietary changes can make a real difference in how often they come back.
Preventing Recurrence
Beyond addressing nutritional gaps, a few practical habits can reduce how often canker sores appear. Avoid biting the inside of your cheeks or lips, which is a common trigger. If you wear braces or a dental appliance that rubs against your mouth, ask your orthodontist about dental wax to create a buffer. Spicy, acidic, and rough-textured foods (chips, crusty bread) can irritate the mouth lining and either trigger new ulcers or aggravate existing ones.
You may have heard that switching to a toothpaste free of sodium lauryl sulfate (SLS), a common foaming agent, can help. The evidence here is mixed. A 2019 review found there wasn’t enough data to confirm that SLS-free toothpaste reduced ulcer frequency, duration, or pain. One double-blind study found no significant change in ulcer patterns after switching. It’s a low-risk thing to try if nothing else is working, but don’t expect dramatic results.
Stress management also matters. Stress is one of the most consistently reported triggers for canker sores, and many people notice flare-ups during high-pressure periods at work or school. Sleep, exercise, and whatever helps you decompress aren’t just general wellness advice; for ulcer-prone people, they’re genuinely preventive.
When an Ulcer Needs Attention
A single canker sore that heals within two weeks is normal and not a cause for concern. But certain patterns warrant a closer look: ulcers larger than a centimeter across, sores that last longer than three weeks, ulcers that keep recurring in clusters, sores accompanied by fever, or any ulcer that is completely painless (painless ulcers can occasionally indicate something other than a canker sore). In these cases, a dentist or doctor can examine the sore, run blood work to check for deficiencies or underlying conditions, and recommend a targeted treatment plan.