Most mouth ulcers heal on their own within two weeks, but the right treatment can cut pain significantly and speed things along. The key is matching your approach to the severity of the ulcer: simple home remedies work well for small sores, over-the-counter products add a layer of relief, and persistent or large ulcers sometimes need prescription-strength options.
What Type of Ulcer You’re Dealing With
Mouth ulcers (also called canker sores or aphthous ulcers) come in three sizes, and the size determines how long you’ll be waiting for relief. Minor canker sores are smaller than a centimeter across, roughly the size of a pea or smaller. These are by far the most common type and typically heal within two weeks without scarring.
Major canker sores are larger than one centimeter. They can take months to heal, often leave scars, and are more likely to need medical treatment. Herpetiform canker sores are clusters of tiny pinpoint ulcers that merge together. Despite the name, they aren’t caused by the herpes virus. They usually resolve in about two weeks.
One important distinction: mouth ulcers and cold sores are not the same thing. Mouth ulcers appear inside the mouth, have no known single cause, and are not contagious. Cold sores (fever blisters) appear on the outside of the mouth around the lips, are caused by herpes simplex virus, and spread easily through contact. The treatments are completely different, so identifying which one you have matters.
Home Remedies That Actually Work
A saltwater rinse is the simplest starting point. Dissolve half a teaspoon of salt in a cup of warm water and swish for 30 seconds a few times a day. It stings briefly but helps keep the area clean and can reduce inflammation.
Honey is worth trying if you have it on hand. In a randomized trial comparing honey applied three times daily to a standard prescription steroid paste, honey reduced ulcer size by 59% within the first few days and achieved complete healing on the same timeline as the steroid. Pain scores dropped by about 48% with both treatments. Where honey actually outperformed the steroid was in reducing burning sensation: a 55% decrease compared to 30% with the medication. Apply a small amount of raw honey directly to the ulcer after meals.
Avoiding certain foods also makes a real difference while you’re healing. Acidic foods (citrus, tomatoes, vinegar-based dressings), spicy dishes, and rough or crunchy textures like chips and toast all irritate the exposed tissue and can extend healing time.
Over-the-Counter Products
If home remedies aren’t enough, pharmacy options fall into two categories: pain relievers and protective barriers.
For pain, look for products containing benzocaine, a topical numbing agent that temporarily blocks nerve signals at the ulcer site. Gels and liquids with benzocaine provide fast but short-lived relief, usually lasting 15 to 30 minutes. Apply directly to the dried ulcer surface for the best effect.
Protective pastes and patches create a physical barrier over the sore, shielding it from food, drinks, and your teeth. These tend to offer longer relief than numbing gels alone, and some contain both a barrier and an active pain-relieving ingredient. Antiseptic mouthwashes formulated for mouth sores can also help prevent secondary infection, which slows healing.
When You Need Something Stronger
For ulcers that are large, extremely painful, or keep coming back, doctors have several prescription-level tools. Topical steroid pastes are the most common first step. These are applied directly to the ulcer to suppress the inflammatory response driving the pain and tissue damage.
Medicated mouth rinses are another option. Some formulations combine a numbing agent, an antacid to coat the tissue, and an antihistamine to reduce swelling. These are swished around the mouth several times daily. Antibiotic rinses have also been shown to reduce ulcer duration in some cases.
For severe recurrent ulcers that don’t respond to topical treatments, oral corticosteroids or other systemic medications may be necessary. This level of treatment is reserved for people who experience frequent, debilitating outbreaks that significantly affect eating and daily life.
Preventing the Next One
If you get mouth ulcers repeatedly, your toothpaste may be a factor. Sodium lauryl sulfate (SLS) is a foaming agent in most toothpastes, and it irritates the soft tissue inside the mouth. A meta-analysis published through the American Dental Association found that switching to an SLS-free toothpaste resulted in a statistically significant reduction in the number of ulcers. Across the pooled studies, patients using SLS-free toothpaste developed roughly one fewer ulcer per recurrence cycle on average. Several studies within the analysis showed an even larger effect, with reductions of over four fewer ulcers. SLS-free toothpastes are widely available from most major brands.
Other common triggers include biting the inside of your cheek, poorly fitting dental work, stress, hormonal changes, and nutritional deficiencies in iron, vitamin B12, or folate. If your ulcers are frequent, keeping a simple log of when they appear can help you identify a personal pattern. Some people notice flare-ups tied to specific foods, menstrual cycles, or stressful periods.
Signs That Need Medical Attention
Most mouth ulcers are harmless and temporary. But certain patterns warrant a visit to your doctor or dentist. These include sores lasting three weeks or longer, new ulcers appearing before old ones finish healing, unusually large ulcers, sores that are painless (which can sometimes signal something other than a typical canker sore), pain that doesn’t respond to any treatment, or ulcers accompanied by fever or diarrhea. Any sore appearing on the outer part of your lips rather than inside the mouth should also be evaluated, as this suggests a different condition entirely.