Most mouth sores heal on their own within 10 to 14 days, but the right treatment can cut pain significantly and speed up recovery. What you should do depends on the type of sore you’re dealing with, how large it is, and how often it comes back. Here’s how to identify what you have and treat it effectively.
Canker Sores vs. Cold Sores
The easiest way to tell these apart is location. Cold sores (fever blisters) appear on the outside of your mouth, usually around the border of your lips. They look like clusters of small, fluid-filled blisters and are caused by the herpes simplex virus. They’re contagious.
Canker sores show up inside the mouth, on the inner cheeks, lips, or tongue. They’re typically a single round sore, white or yellow in the center with a red border. They’re not contagious and don’t have a single known cause, though injuries to the mouth, stress, smoking, and nutritional deficiencies can all trigger them. The treatments below focus primarily on canker sores and other sores inside the mouth, since these are the most common reason people search for relief.
Salt Water Rinses
The simplest and cheapest treatment is a salt water rinse. Dissolve 1 teaspoon of salt in 8 ounces of warm water. Swish it around your mouth for 15 to 20 seconds, then spit. If the rinse stings too much, cut the salt to half a teaspoon for the first day or two. You can repeat this several times a day, especially after meals, to keep the area clean and reduce irritation.
Salt water won’t numb the pain the way a medicated gel will, but it creates a less hospitable environment for bacteria and helps draw out fluid from inflamed tissue. For mild sores that you catch early, this may be all you need.
Over-the-Counter Gels and Rinses
For more noticeable pain, pharmacy products can help in two ways: numbing the sore and protecting it from further irritation. Look for products with these active ingredients:
- Benzocaine (found in products like Anbesol, Zilactin-B, and Orabase) numbs the sore on contact. Apply it directly as a paste or gel.
- Hydrogen peroxide rinses (such as Orajel Antiseptic Mouth Sore Rinse or Peroxyl) clean the sore and help prevent secondary infection.
The key with any topical product is applying it as soon as you notice the sore forming. Early treatment makes a noticeable difference in both pain levels and healing time. Reapply as directed on the packaging, typically before meals or at bedtime when the sore is most bothersome.
When You Might Need a Prescription
Minor canker sores, the most common kind, generally heal within 10 to 14 days without medical treatment. But major canker sores can take up to six weeks to heal and sometimes leave scars. If you’re dealing with large, deep, or frequently recurring sores, a prescription steroid paste or rinse can change the course of healing significantly. These work by reducing the inflammation driving the sore, which speeds up tissue repair.
Some people experience recurrent episodes two to three times a year with relatively mild pain that resolves in a few days. That’s considered normal and rarely needs prescription treatment. But if your sores are lasting 10 days or longer per episode, are intensely painful, or keep returning despite your efforts to manage triggers, a prescription-strength approach is reasonable. Your dentist or doctor can also prescribe a medicated mouthwash for more widespread sores.
Foods That Make Mouth Sores Worse
What you eat while a sore is healing matters more than most people realize. Certain foods directly irritate the exposed tissue and can extend healing time. Avoid these until the sore closes:
- Acidic foods and drinks: orange juice, grapefruit, lemon, lime, tomato sauce, pineapple
- Spicy foods: hot peppers, salsa, curry
- Hard or crunchy foods: dry toast, crackers, chips, raw carrots
- Very hot foods and beverages: fresh coffee, hot soup straight from the stove
Stick with soft, cool, or room-temperature foods while you’re healing. Yogurt, scrambled eggs, mashed potatoes, smoothies, and oatmeal are all easy on sore tissue. If you’re drinking juice, avoid citrus and tomato varieties entirely.
Nutritional Deficiencies and Recurring Sores
If you get canker sores repeatedly, the cause may be nutritional rather than mechanical. Deficiencies in vitamin B12, folate, and iron are all linked to recurrent outbreaks. B12 deficiency in particular is well documented as a trigger. If your sores keep coming back and you can’t identify an obvious cause like biting your cheek or a sharp tooth edge, ask your doctor to check your levels with a blood test.
Correcting a B12 deficiency through daily oral supplements often reduces the frequency of outbreaks. Folate deficiency is similarly treatable with supplementation. These aren’t quick fixes for the sore you have right now, but they can break the cycle of sores returning every few months.
Switch to SLS-Free Toothpaste
Most commercial toothpastes contain sodium lauryl sulfate (SLS), a foaming agent that can damage the delicate lining of your mouth. Research shows SLS strips away the protective mucin layer inside the mouth, exposing the tissue underneath and triggering canker sores in susceptible people. A clinical study of 30 patients with frequent canker sores found that switching to an SLS-free toothpaste significantly reduced the duration of sores and lowered daily pain scores compared to standard toothpaste.
SLS-free toothpastes are widely available at most pharmacies and grocery stores. Brands like Sensodyne (some formulations), Biotene, and several natural toothpaste brands skip SLS. Check the ingredients list for “sodium lauryl sulfate.” If you get canker sores more than a couple of times a year, this one change is worth trying before anything else.
Signs a Mouth Sore Needs Medical Attention
Most mouth sores are harmless, but some warrant a closer look. Oral cancer can initially resemble a canker sore, appearing as a sore or white or reddish patch inside the mouth that simply won’t heal. Other warning signs include a lump or growth inside the mouth, loose teeth without an obvious dental cause, pain in your ear, or difficulty swallowing or opening your mouth.
The two-week rule is the standard guideline: if any mouth sore persists for more than two weeks without improvement, have it evaluated by a dentist or doctor. This is especially important if you use tobacco or drink alcohol heavily, both of which increase oral cancer risk. A persistent sore is almost certainly not cancer, but it’s the kind of thing that’s easy to check and important not to ignore.