Most canker sores on the tongue heal on their own within a few weeks, but the pain can make eating and talking miserable in the meantime. Minor sores, the most common type, are smaller than a pea and typically resolve without scarring. The good news is that several treatments can reduce pain and speed healing while you wait.
Rinses That Reduce Pain Fast
The simplest treatment is a saltwater or baking soda rinse. Dissolve one teaspoon of baking soda in half a cup of warm water, swish gently for 30 seconds, and spit. You can do the same with a half teaspoon of salt in the same amount of water. These rinses help neutralize acids in your mouth and create a less irritating environment for the sore. Repeating this several times a day, especially after meals, keeps the area cleaner and can noticeably cut down on stinging.
Over-the-counter mouth rinses containing hydrogen peroxide (diluted to about 1.5%) work similarly by keeping the ulcer clean. Look for antiseptic rinses labeled for mouth sores at any pharmacy.
Topical Gels and Pastes
Numbing gels containing benzocaine are available without a prescription and can temporarily block pain on the tongue. Apply a small amount directly to the sore before meals to make eating more comfortable. Because the tongue is constantly moving and wet, gels tend to wear off faster here than on other parts of the mouth, so reapply as needed throughout the day.
For sores that are especially large or painful, a doctor or dentist can prescribe a steroid dental paste. This type of paste reduces inflammation directly at the sore. You press a small amount onto the ulcer with a cotton swab after meals and at bedtime, forming a thin protective film. The key is to press it on gently rather than rubbing, which causes the paste to crumble and lose its protective coating.
Foods to Avoid While Healing
Acidic and rough-textured foods are the biggest enemies of a canker sore on the tongue, because everything you eat passes right over it. While the sore is active, try to cut back on or avoid:
- Citrus fruits and juices: oranges, grapefruits, lemons, limes, and pineapple
- Tomatoes and tomato-based sauces or soups
- Coffee, which contains acids that irritate soft tissue
- Soda, including diet versions, which are just as acidic as regular
- Strawberries and other high-acid fruits
Spicy foods and anything with sharp edges (chips, crusty bread, hard pretzels) can also reopen or aggravate the sore. Stick with softer, bland foods until it closes up. Cool or room-temperature foods tend to be more comfortable than hot ones.
Why You Keep Getting Them
If canker sores come back frequently, the cause often traces to one of a few common triggers. One that surprises many people is their toothpaste. Sodium lauryl sulfate (SLS), the foaming agent found in most major toothpaste brands, is a known soft tissue irritant. It’s the same ingredient used in shampoos and household cleaners. Switching to an SLS-free toothpaste is one of the easiest changes you can make. Brands like Sensodyne ProNamel, Tom’s of Maine, Hello, and Arm & Hammer all make SLS-free options.
Nutritional deficiencies are another overlooked cause. Recurrent canker sores have been linked to low levels of vitamin B12, iron, zinc, and folate. B12 supports nerve and cell health, zinc plays a role in immune function and wound healing, and iron and folate are essential for healthy blood cell production. If you get canker sores regularly and can’t identify an obvious trigger, it may be worth asking your doctor to check these levels with a simple blood test.
Stress, lack of sleep, and minor injuries to the tongue (biting it, poking it with a toothbrush, or irritation from braces) are other frequent culprits. Some people notice a pattern where sores appear during high-stress periods, which likely relates to temporary dips in immune function.
Minor Sores vs. Major Sores
Minor canker sores make up the vast majority of cases. They’re less than one centimeter across, moderately painful, and heal within a few weeks without leaving a scar. They respond well to the home treatments described above.
Major canker sores are a different experience. They’re larger than one centimeter, extremely painful, and can take months to heal. They often leave scars. If you have a sore this size, or if it hasn’t started improving after two weeks, it’s worth getting it evaluated professionally. A dentist or doctor can prescribe stronger treatments, including steroid pastes or oral medications, to bring the inflammation under control.
When a Sore Needs Professional Evaluation
Most tongue sores are harmless, but certain signs overlap with more serious conditions, including oral cancer. A sore that persists for more than two weeks without healing, a white or reddish patch that doesn’t go away, unexplained ear pain, or difficulty swallowing all warrant a visit to your doctor or dentist. Oral cancer sores typically don’t heal the way canker sores do. They may feel firm or lumpy rather than soft. A quick examination can rule out anything concerning and give you peace of mind.