Most canker sores heal on their own within one to two weeks, but the right home care can reduce pain and speed things along. These small, shallow ulcers on the inside of your mouth are not contagious (unlike cold sores on the lips), and a combination of simple rinses, smart food choices, and over-the-counter products can make the days until healing far more comfortable.
What Canker Sores Are and How Long They Last
Canker sores, known clinically as aphthous ulcers, are open sores that form on the soft tissue inside your cheeks, along your gums, on your tongue, or on the roof of your mouth. They come in three types. Minor canker sores, the most common kind, are less than 1 centimeter across and shallow. They account for the vast majority of cases and typically clear up within one to two weeks without scarring. Major canker sores are larger and deeper, and they can take weeks or even months to fully heal. These sometimes leave scars. The third type, herpetiform canker sores, appear as clusters of many tiny sores that can merge together.
If you’re dealing with a single small sore that showed up after you bit your cheek or ate something sharp, it’s almost certainly a minor canker sore, and it will resolve with basic care.
Home Rinses That Help
The simplest and most effective first step is a mouth rinse you can make at home. Dissolve 1 teaspoon of baking soda in half a cup of warm water and swish it around your mouth for 30 seconds, then spit. A salt water rinse works similarly. Either option helps keep the sore clean, reduces bacteria around the wound, and creates conditions that support faster healing. You can repeat these rinses several times a day, especially after meals.
Over-the-Counter Products
Pharmacy shelves carry several products designed specifically for canker sores. Topical gels and pastes containing a numbing agent provide temporary pain relief and can make eating much easier. Look for products marketed as oral pain relievers or canker sore patches. Protective pastes create a barrier over the sore, shielding it from further irritation by food, teeth, and tongue movement. Antiseptic rinses formulated for mouth sores can also keep the area clean and reduce the chance of secondary infection.
Apply any topical product after rinsing and gently drying the area with a tissue. Putting a gel or paste on a wet sore means it slides off almost immediately.
Foods to Avoid While You Heal
What you eat during an active canker sore matters more than most people realize. Certain foods directly irritate the open tissue and can delay healing.
- Spicy foods: Hot peppers, sriracha, salsa, curry, cayenne, and crushed red pepper flakes all contain compounds that burn exposed tissue.
- Acidic foods and drinks: Citrus fruits, tomatoes, berries, pineapple, vinegar, coffee, alcohol, and fruit juice cause stinging and can slow recovery.
- Hard and crunchy foods: Granola, pretzels, crusty bread, popcorn, potato chips, and crackers can scrape the sore and reopen it.
- Hot-temperature foods: Heat intensifies pain from mouth sores. Let food cool before eating.
Stick with soft, bland, room-temperature foods until the sore closes. Think yogurt, scrambled eggs, mashed potatoes, oatmeal, and smoothies (skip the citrus). Using a straw can help liquids bypass a sore on the front of your mouth or tongue.
Why Some People Get Canker Sores Repeatedly
If canker sores are a recurring problem for you, nutrition may be part of the picture. Researchers have linked deficiencies in vitamin B12, folic acid, iron, and other B vitamins to recurrent canker sores. In one clinical trial published in the Journal of the American Dental Association, 1,000 micrograms of sublingual vitamin B12 taken daily for six months led to impressive results: 74 percent of participants in the B12 group were completely free of ulcers by the end of the trial, compared with just 32 percent in the placebo group. This effect held even among people whose B12 blood levels were normal at the start.
Correcting a folic acid or iron deficiency, when one exists, has also been shown to reduce or eliminate recurrent outbreaks. If you get canker sores more than a few times a year, a blood test checking these levels is a reasonable step. A daily multivitamin or B-complex supplement is a low-risk option while you investigate.
Beyond nutrition, common triggers for recurrent canker sores include stress, hormonal changes, minor mouth injuries from dental work or aggressive brushing, and certain toothpaste ingredients. Sodium lauryl sulfate, the foaming agent in many toothpastes, has been linked to canker sore flare-ups in some people. Switching to an SLS-free toothpaste is an easy experiment if you’re prone to outbreaks.
Natural Remedies Worth Trying
Honey applied directly to a canker sore has been used as a folk remedy for centuries, and there’s some clinical support behind it. Honey has natural antibacterial properties and creates a protective coating over the wound. Applying a small amount to the sore several times a day, especially before bed, may reduce pain and support healing.
Propolis, the resinous substance bees use to seal their hives, has also shown promise. Small placebo-controlled studies have found that applying propolis ointment to oral sores three times a day helped them heal faster than no treatment. Propolis products are available as lip balms, oral sprays, and tinctures at most health food stores. If you have a known allergy to bee products, skip this one.
When a Canker Sore Needs Professional Attention
Most canker sores don’t need a doctor. But certain patterns signal something beyond a routine sore. See a dentist or doctor if a canker sore lasts longer than three weeks, is unusually large, spreads rather than shrinks, comes with a high fever, or makes it impossible to drink fluids. Frequent recurrences (more than three or four times a year) also warrant investigation, since persistent canker sores can occasionally signal an underlying condition like celiac disease, an immune disorder, or a nutritional deficiency that needs treatment.
For severe or stubborn sores, a healthcare provider can prescribe stronger treatments, including corticosteroid rinses that reduce inflammation or chemical cauterization to seal the sore and provide rapid pain relief.