Most canker sores heal on their own within 10 to 14 days, but the right combination of treatments can cut that time significantly and reduce pain in the meantime. The key is acting early: treatments started within the first day or two of a sore appearing tend to work best, before the ulcer fully develops.
What You’re Working With
A typical canker sore is small, usually 2 to 3 millimeters across and less than 8 millimeters at its widest. These minor sores heal within about 10 days without scarring. Some people get mild versions that clear up in just 2 to 3 days with no treatment at all, while others deal with more painful ulcers lasting up to 10 days.
If your sore is larger than a centimeter (roughly the width of your pinky fingernail), it falls into the “major” category. Major canker sores can take six weeks or longer to heal and may leave a scar. These deserve a trip to your dentist or doctor rather than home management alone.
Rinses That Actually Help
A saltwater rinse is the simplest first step, and it does more than just “clean” the sore. Salt water kills bacteria through osmosis, pulling water out of bacterial cells. It also shifts the pH inside your mouth toward alkaline, which makes the environment hostile to the harmful bacteria that thrive in acidic conditions. On top of that, salt water promotes the migration of fibroblasts, the cells responsible for wound repair, and increases the structural proteins that regulate healing.
Dissolve about half a teaspoon of salt in a cup of warm water and swish for 30 seconds, two to three times a day. You can alternate this with a baking soda rinse (one teaspoon of baking soda in half a cup of water), which works on the same pH-shifting principle. Neither will sting as badly as you might expect, though the first few seconds on an open sore can be uncomfortable.
OTC Treatments Worth Trying
Topical numbing gels containing benzocaine (sold as Orajel and similar brands) won’t speed healing, but they provide immediate pain relief that lasts 15 to 30 minutes per application. This matters because pain often keeps people from eating and drinking normally, which slows recovery. Apply a thin layer directly to the sore before meals.
For something that targets both pain and healing time, look for products containing a steroid like triamcinolone. A large network meta-analysis comparing dozens of topical treatments found that triamcinolone significantly reduced both ulcer size and pain symptoms compared to placebo. It works by calming the inflammatory response that keeps the sore angry and swollen. These are available as prescription pastes in the U.S., so ask your dentist or doctor if your sores are recurrent.
Milk of magnesia, dabbed directly onto the sore with a cotton swab three to four times a day, is an underrated option. The magnesium hydroxide neutralizes acid at the sore’s surface, shifts the local pH to make the environment less favorable for the ulcer, and coats the wound to protect it from further irritation.
Honey Outperforms Most Home Remedies
If you’re looking for a single home remedy backed by clinical data, honey is the strongest option. In the same network meta-analysis, honey ranked among the top interventions for speeding healing, reducing total healing time by roughly 3.5 days compared to no treatment. It likely works through a combination of its natural antibacterial properties, its ability to maintain a moist wound environment, and anti-inflammatory compounds.
Use raw, unpasteurized honey. Dab a small amount directly on the sore several times a day, especially after meals and before bed. Let it sit rather than rinsing it away. It will sting briefly on contact, then the coating effect tends to soothe.
What Your Dentist Can Do
If you need a canker sore gone fast for an event, presentation, or just because the pain is interfering with your life, a dental laser treatment is the most dramatic option. Some dental offices report healing times of about one day after laser treatment, compared to the usual 10 days. The laser essentially seals the nerve endings (stopping pain almost immediately) and stimulates the tissue to repair itself faster. Not every dental office offers this, so call ahead.
Chemical cauterization is another professional option. A product called Debacterol chemically cauterizes the sore and can reduce healing time to about a week. Silver nitrate, the other common cauterizing agent, helps with pain relief but hasn’t been shown to speed up healing itself. Both are single-application treatments done in the office.
Prevent the Next One
Check your toothpaste for sodium lauryl sulfate (SLS), the foaming agent in most mainstream brands. In a clinical trial with 90 participants, those who switched to SLS-free toothpaste reported that their canker sores didn’t last as long and caused less pain compared to periods when they used SLS-containing toothpaste. Separate research has found that switching to SLS-free toothpaste reduces how often canker sores appear in the first place. Brands like Sensodyne, Biotene, and Verve are SLS-free and widely available.
Beyond toothpaste, common triggers include acidic foods (tomatoes, citrus, pineapple), spicy foods, and physical trauma from braces, sharp chip edges, or accidentally biting your cheek. Stress and sleep deprivation are also well-established triggers. If you’re getting canker sores more than three times a year, keeping a simple log of what you ate and how you slept in the days before each outbreak can help you identify your personal pattern.
A Practical Healing Plan
For the fastest results, layer your approach rather than relying on a single remedy. Start with a saltwater or baking soda rinse to clean the area and shift the pH. Then apply honey or milk of magnesia directly to the sore. Use a numbing gel before meals so you can eat comfortably. Repeat this cycle three to four times a day.
Avoid crunchy, acidic, or spicy foods that will re-traumatize the tissue. Stick with soft, cool, or room-temperature foods. Yogurt, smoothies, scrambled eggs, and oatmeal are all easy on mouth sores. Drinking through a straw can help keep acidic or irritating beverages away from the affected area.
If the sore hasn’t started shrinking after five to seven days, is larger than a centimeter, or you’re running a fever alongside it, that’s worth a professional evaluation. Persistent or unusually large ulcers occasionally signal nutritional deficiencies (iron, B12, or folate), celiac disease, or other underlying conditions that simple topical treatment won’t address.