Most mouth blisters are canker sores, and the majority heal on their own within two weeks. But you can speed that process and cut the pain significantly with the right combination of rinses, topical treatments, and a few simple habit changes. The approach depends on what type of sore you’re dealing with and how severe it is.
Identify What You’re Dealing With
The two most common types of mouth blisters are canker sores and cold sores, and they require different treatment. Canker sores (aphthous ulcers) appear inside the mouth on soft tissue like the inner cheeks, tongue, or floor of the mouth. They’re round, shallow, and typically have a white or yellowish center with a red border. They are not contagious, and their exact cause is still unknown.
Cold sores are caused by herpes simplex virus (HSV-1), which infects 60% to 95% of adults worldwide. They usually appear on or around the lips, though they can occasionally show up on the hard palate. About 60% of people feel a tingling or burning sensation before a cold sore surfaces, and blistering follows within 24 hours. Cold sores are contagious, especially when blisters are open.
If your blisters are inside the mouth on soft, movable tissue, you’re almost certainly dealing with canker sores. If they’re on your lips or the hard roof of your mouth and started with a tingling feeling, they’re likely cold sores. This distinction matters because cold sores respond to antiviral treatment, while canker sores do not.
Salt Water and Baking Soda Rinses
A simple mouth rinse is the fastest thing you can do at home to reduce pain and support healing. 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. The salt helps draw fluid from swollen tissue, and the baking soda neutralizes acids in your mouth that irritate open sores.
Rinse three to four times a day, especially after meals. This keeps food particles from settling into the ulcer and creating more irritation. It’s free, it works immediately for mild pain relief, and it’s safe to use alongside any other treatment.
Over-the-Counter Products That Help
For faster pain relief, OTC products with benzocaine (found in brands like Anbesol, Orabase, and Zilactin-B) numb the area on contact. Apply them directly to the sore as soon as it appears for the best results. These come as gels, pastes, or liquids, and you can reapply several times a day.
Hydrogen peroxide rinses, like Orajel Antiseptic Mouth Sore Rinse, clean the ulcer and reduce bacteria in the area. These are particularly helpful if the sore developed after you bit your cheek or burned your mouth on hot food, since traumatic wounds are more vulnerable to infection. Don’t swallow the rinse, and follow the product’s instructions for dilution.
For cold sores specifically, look for OTC creams containing docosanol, which can shorten an outbreak by about a day when applied at the first sign of tingling.
Honey as a Topical Treatment
Applying honey directly to mouth ulcers is one of the better-supported natural remedies. A systematic review of 13 studies found that honey reduced either the severity or healing time of oral ulcers in 12 of them. The effect was especially strong for ulcers caused by cancer treatments, where honey consistently reduced symptoms. For standard canker sores, the measured differences in ulcer size and pain were modest compared to conventional treatments, but patients still reported feeling better.
Use raw, unpasteurized honey. Dab a small amount onto the sore a few times a day, letting it sit as long as you can before eating or drinking. It forms a protective coating and has natural antibacterial properties.
Prescription Options for Severe Sores
If your sores are larger than 1 centimeter, last longer than two weeks, or keep coming back, a prescription-strength treatment may be necessary. The most common option is a steroid dental paste containing triamcinolone acetonide. You press a small dab (about a quarter inch) onto the sore until a thin film develops. Apply it at bedtime so the medication stays in contact with the ulcer overnight. For more severe cases, you may need to apply it two or three times a day, ideally after meals.
This paste reduces inflammation and pain but doesn’t cure the underlying cause of recurrent sores. Major canker sores, which account for 5% to 10% of cases, can grow larger than 1 centimeter, persist for up to six weeks, and leave scarring. These almost always benefit from prescription treatment rather than just home care.
How Long Healing Takes
Healing timelines depend on the type and size of the sore:
- Minor canker sores (under 1 cm): typically heal within 2 weeks. These represent 75% to 85% of all canker sore cases.
- Major canker sores (1 to 3 cm): can take up to 4 weeks and may leave a scar.
- Herpetiform canker sores (clusters of tiny ulcers that merge together): heal in 2 to 4 weeks.
You’ll know healing is underway when the pain decreases and the white or yellow center starts to shrink. The redness around the edges gradually fades. If a sore isn’t showing any improvement after a week of home treatment, or if it’s getting larger, that’s a signal to try a stronger approach.
Preventing Recurrence
Recurring mouth sores often have a nutritional component. Deficiencies in vitamin B12, folate, and iron are all linked to mouth ulcers. A red, sore tongue with recurring ulcers is a classic sign of B12 or folate deficiency. If your sores keep coming back, it’s worth having your levels checked. Eating more leafy greens, fortified cereals, eggs, and lean meats can help close common gaps.
Other practical steps that reduce recurrence: switch to a toothpaste without sodium lauryl sulfate (SLS), which is a foaming agent that irritates oral tissue in some people. Avoid acidic foods like citrus, tomatoes, and vinegar-based dressings when you feel a sore forming. Stress is a well-known trigger, so persistent outbreaks during high-pressure periods aren’t coincidental.
Signs That Need Professional Evaluation
A mouth sore that doesn’t heal within two weeks deserves attention. The Mayo Clinic lists several signs that overlap with oral cancer: a sore that won’t heal, a white or reddish patch inside the mouth, a lump or growth, unexplained mouth or ear pain, painful swallowing, or loose teeth. Any single one of these persisting beyond two weeks warrants a professional exam. This is especially true for sores that are painless, since canker sores hurt, but early oral cancers often don’t.