Most canker sores are minor, measuring less than 5 mm across, and heal on their own within 7 to 14 days. But you don’t have to just wait it out. Several treatments, from simple salt rinses to over-the-counter gels, can cut the pain and speed up healing significantly. What works best depends on how severe and how frequent your sores are.
What Type of Canker Sore You’re Dealing With
About 80% of canker sores are the minor type: small, round, shallow ulcers that clear up in one to two weeks without scarring. These are the ones most people search for help with, and they respond well to home treatment.
Major canker sores are larger, deeper, and can take weeks or even months to heal, often leaving scars. Herpetiform canker sores show up as clusters of tiny pinpoint ulcers that can merge together, typically resolving within about a month. If your sores are unusually large, come in clusters, or haven’t healed after two weeks, that’s a different situation that likely needs professional treatment.
Home Remedies That Actually Help
A salt water rinse is the simplest and most widely recommended starting point. St. Jude Children’s Research Hospital uses a formula of 1 teaspoon of table salt and 1 teaspoon of baking soda dissolved in 4 cups of warm water. Swish gently for 30 seconds a few times a day, especially after meals. The salt draws fluid from the sore to reduce swelling, while the baking soda neutralizes acids that irritate the wound.
Honey applied directly to the sore is more than folk medicine. A randomized controlled trial of 94 patients with minor canker sores found that honey significantly outperformed a topical steroid paste in reducing ulcer size, pain, and redness. No side effects were reported. To try it, dab a small amount of raw honey onto the sore several times a day. It forms a protective coating that shields the ulcer from further irritation.
Avoid foods that slow healing or make the pain worse while you have an active sore. The biggest culprits are acidic foods (citrus fruits, tomatoes, strawberries, coffee), spicy foods (hot peppers, curry, salsa), and anything with rough or sharp edges (chips, pretzels, nuts, seeds). These either chemically irritate the open wound or physically scrape against it.
Over-the-Counter Treatments
OTC products work best when applied as soon as you feel a sore forming. The key active ingredients to look for are benzocaine, which numbs the area on contact, and hydrogen peroxide rinses, which clean the sore and reduce bacteria. Products like Orajel, Anbesol, and Zilactin-B contain benzocaine and create a temporary protective film over the ulcer.
Apply these directly to the sore after drying the area with a tissue. Reapply as directed, typically before meals and at bedtime. The numbing effect is temporary, lasting 30 minutes to an hour, but the protective barrier helps the sore heal faster by keeping food and saliva from constantly aggravating it.
Switch to SLS-Free Toothpaste
If you get canker sores repeatedly, your toothpaste may be part of the problem. Sodium lauryl sulfate (SLS) is a foaming agent in most toothpastes, and it strips away a protective layer of moisture from the inside of your mouth. A systematic review of four clinical trials found that switching to SLS-free toothpaste significantly reduced the number of ulcers, how long they lasted, how many episodes people experienced, and how much pain they caused. Brands like Sensodyne, Biotene, and some versions of Tom’s of Maine are SLS-free. Check the ingredients list on the back of the tube.
Prescription Options for Stubborn Sores
When OTC treatments aren’t enough, doctors and dentists can prescribe stronger options. A steroid dental paste is applied directly to the sore at bedtime so the medication stays in contact with the ulcer overnight. You press a small dab onto the lesion until a thin film forms, without rubbing it in. Depending on severity, you may need to apply it two or three times a day, ideally after meals.
For multiple sores at once, a prescription steroid mouth rinse reduces inflammation across the entire mouth. A prescription numbing rinse can also be used to manage pain before eating.
Laser therapy offered by some dental offices provides near-immediate pain relief. In one controlled trial, 28 out of 30 patients experienced complete pain relief right after a single laser session. Sores in the treated group healed in about 3 days on average, compared to nearly 9 days in the untreated group. It’s not widely available everywhere and may not be covered by insurance, but it’s worth asking about if you deal with frequent or severe outbreaks.
Nutritional Deficiencies and Recurrent Sores
People who get canker sores over and over again are more likely to be low in certain nutrients. Studies have found nutritional deficiencies in roughly 14 to 18% of patients with recurrent canker sores, most commonly low levels of vitamin B12, folate, and iron. These nutrients play essential roles in maintaining healthy tissue inside the mouth.
You don’t need to start supplementing blindly. If your sores keep coming back every few weeks, a simple blood test can check these levels. Foods rich in B12 include meat, fish, eggs, and fortified cereals. Folate is abundant in leafy greens, beans, and citrus. Iron comes from red meat, lentils, and spinach. Correcting a deficiency, if one exists, can reduce how often sores appear.
Red Flags Worth Taking Seriously
A typical minor canker sore should be noticeably improving within a week and fully healed within two. Any oral sore that persists for two weeks or longer after you’ve removed potential irritants warrants professional evaluation. The same goes for sores that are unusually large, spreading, accompanied by high fever, or making it difficult to drink fluids. Persistent sores that don’t respond to treatment may need a biopsy to rule out other conditions.