Most canker sores heal on their own within one to two weeks, but the right combination of rinses, topical treatments, and dietary changes can cut that time shorter and reduce pain significantly while you wait. The key is starting treatment as early as possible, ideally when you first feel that telltale tingling or spot of tenderness inside your mouth.
Salt Water and Baking Soda Rinses
The simplest and cheapest remedy is one you can make right now. Mix 1 teaspoon of salt and 1 teaspoon of baking soda into 4 cups (one quart) of water. Swish it around your mouth for 15 to 30 seconds, then spit. Repeat every four to six hours, or more often if the pain is bothering you. You can also use salt alone or baking soda alone if you prefer. The salt draws fluid from the swollen tissue, which helps reduce inflammation, while the baking soda neutralizes acids in your mouth that irritate the open sore.
Over-the-Counter Topical Treatments
Pharmacy shelves have several options that numb pain and form a protective barrier over the ulcer. Look for products containing benzocaine, a local anesthetic sold under brand names like Anbesol, Orabase, and Zilactin-B. Hydrogen peroxide rinses (like Orajel Antiseptic Mouth Sore Rinse or Peroxyl) work as antiseptics, keeping the area clean and helping it heal faster.
The most important thing with any topical product is timing. Apply it as soon as the sore appears. The earlier you start, the more you shorten the overall healing window. Reapply according to the package directions, especially after eating or drinking, since food and saliva wash the product away quickly.
Honey as a Topical Treatment
Plain honey applied directly to the sore is surprisingly effective. In a randomized controlled trial, patients who dabbed honey on their canker sores saw the ulcer shrink and heal in about 2.7 days on average, compared with nearly 6 days for those using a standard prescription steroid paste. Honey has natural anti-inflammatory and antimicrobial properties, and it also forms a soothing coating that protects the sore from further irritation. Use a clean finger or cotton swab to apply a small amount directly to the ulcer a few times a day. Raw, unprocessed honey tends to work best.
Foods That Make It Worse
What you eat matters more than you might think, both for healing the current sore and preventing the next one. Acidic foods like citrus fruits, tomatoes, and vinegar-based dressings sting on contact and can slow healing. Spicy foods, salty snacks, and anything with rough or sharp edges (think chips, crackers, crusty bread) physically scrape against the ulcer and reopen the wound.
Some foods also seem to trigger canker sores in the first place. Common culprits include caffeine, eggs, cheese, peanuts, and almonds. If you notice a pattern between eating certain foods and developing sores within a day or two, that’s worth paying attention to. While the sore is active, stick to soft, bland, lukewarm foods. Cold foods like yogurt or smoothies can also soothe the pain.
Switch to SLS-Free Toothpaste
Sodium lauryl sulfate (SLS) is a foaming agent in most toothpastes, and it’s a well-documented irritant for people prone to canker sores. A systematic review of clinical trials found that switching to an SLS-free toothpaste significantly reduced the number of ulcers, the duration of each ulcer, the number of recurring episodes, and the level of pain. If you get canker sores more than a couple of times a year, this is one of the easiest long-term changes you can make. Brands like Sensodyne, Biotene, and some versions of Tom’s of Maine are SLS-free. Check the ingredients list for “sodium lauryl sulfate” near the top.
Nutritional Deficiencies and Recurrent Sores
People who get canker sores repeatedly often have lower levels of vitamin B12 and folate (vitamin B9) compared to those who rarely get them. Iron deficiency has also been linked to recurrent outbreaks. These nutrients all play roles in producing healthy red blood cells and maintaining the tissues lining your mouth. Studies have found that roughly 14 to 18 percent of people with recurrent canker sores have a measurable nutritional deficiency, and that correcting the deficiency with supplements improves symptoms.
If your canker sores keep coming back, it’s worth looking at your diet. Foods rich in B12 include meat, fish, eggs, and dairy. Folate is found in leafy greens, beans, and fortified grains. A simple blood test from your doctor can check whether you’re low in any of these nutrients, and supplementation can make a real difference.
When Prescription Treatment Helps
For sores that are unusually large or painful, or when you have several at once, a doctor or dentist can prescribe stronger options. Steroid mouth rinses reduce inflammation and pain more aggressively than anything available over the counter. Prescription-strength numbing rinses are another option for making eating and talking bearable. There’s also a topical solution called Debacterol that chemically cauterizes the sore, which sounds intense but can reduce total healing time to about a week and provides quick pain relief after application.
Make Sure It’s Actually a Canker Sore
Canker sores and cold sores are often confused, but they’re completely different conditions. Canker sores appear inside the mouth, are not contagious, and look like a single round white or yellow spot with a red border. Cold sores appear outside the mouth, typically around the border of the lips, show up as clusters of small fluid-filled blisters, and are caused by the herpes simplex virus. This distinction matters because the treatments are different. Antiviral medications treat cold sores, while the approaches described above are specific to canker sores.
You should also be alert to mouth sores that don’t follow the normal canker sore pattern. Sores lasting three weeks or longer, new sores appearing before old ones heal, unusually large ulcers, painless sores, or sores accompanied by fever or diarrhea all warrant a visit to your doctor or dentist. These can occasionally signal an underlying condition that needs separate attention.