Most canker sores heal on their own within 10 to 14 days, but the right combination of home care and over-the-counter products can cut pain significantly and speed that timeline. What works best depends on how large the sore is and how often you get them.
Know What Type You’re Dealing With
Not all canker sores behave the same way. Minor canker sores, the most common type, are less than 5 millimeters across and heal within about two weeks without scarring. Major canker sores exceed 1 centimeter in diameter, can appear on tougher tissue like the roof of your mouth, and may take up to six weeks to heal, sometimes leaving a scar. A third type, called herpetiform ulcers, starts as clusters of tiny sores (sometimes up to 100 at once) that merge into a larger, irregular wound.
If yours is small and round with a grayish center and red border, it’s almost certainly a minor sore, and the home treatments below should be all you need.
Salt Water and Baking Soda Rinses
A simple mouth rinse is the cheapest and most accessible first step. The goal is to reduce acidity in your mouth, keep the area clean, and create conditions that help the tissue heal faster. St. Jude Children’s Research Hospital recommends 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 out of swollen tissue to reduce inflammation, while baking soda neutralizes mouth acid that irritates the open sore.
Honey as a Topical Treatment
Applying honey directly to a canker sore is more than a folk remedy. Clinical research presented through the International Association for Dental Research found that honey significantly outperformed both a topical steroid and a placebo in reducing ulcer size, number of pain days, and redness. Dab a small amount of raw honey onto the sore several times a day, particularly after eating. It forms a protective coating and has natural anti-inflammatory and antimicrobial properties. The downside is that it washes away easily, so you’ll need to reapply often.
Over-the-Counter Pain Relief
When a canker sore makes eating or talking miserable, numbing products offer temporary relief. Benzocaine gels (sold as Orajel or Anbesol) can be applied directly to the sore to dull pain on contact. For deeper numbing, a 2 percent lidocaine solution applied with a cotton swab works well, though the relief is brief and you’ll need to reapply as needed throughout the day.
Protective pastes that contain ingredients designed to coat the sore and shield it from food, drinks, and your teeth can also help. These barrier products don’t speed healing much, but they make the days while you’re waiting far more comfortable.
In-Office Treatments for Stubborn Sores
If a sore is especially large or painful, a dentist can chemically cauterize it. A product called Debacterol uses chemical cautery to destroy the damaged tissue, which can shorten healing time to about a week. Silver nitrate, another cautery option, hasn’t been shown to speed healing but does help with pain. Both procedures are quick, done in a single visit, and don’t require anesthesia.
Some dental offices now offer low-level laser therapy, which targets the nerve endings around the sore. Most patients feel immediate pain relief during the procedure itself, and the laser stimulates blood flow to the area, encouraging faster tissue repair. No needles or numbing agents are needed.
Preventing Canker Sores From Coming Back
Switch Your Toothpaste
One of the simplest prevention strategies is switching to a toothpaste free of sodium lauryl sulfate (SLS), the foaming agent in most commercial toothpastes. In one frequently cited study, participants who switched from an SLS toothpaste to an SLS-free version went from an average of 14.3 ulcers over three months to just 5.1. That’s a 64 percent reduction from changing nothing but toothpaste. Brands marketed as “sensitive” or “natural” are more likely to be SLS-free, but check the ingredients to be sure.
Check for Nutritional Gaps
Recurrent canker sores are linked to deficiencies in vitamin B12, folate, and iron. In a clinical trial of 160 people with recurring sores, about 9 percent had low B12 levels at the start. A separate randomized trial tested high-dose B12 supplements (1,000 micrograms daily, taken under the tongue) and found that after six months, 74 percent of participants in the supplement group were completely free of ulcers, compared to just 32 percent in the placebo group. If you get canker sores frequently, a blood test to check these levels is worth requesting.
Watch for Physical Triggers
Biting your cheek, aggressive brushing, sharp edges on braces or dental work, and rough-textured foods like chips and crusty bread can all trigger sores in people who are prone to them. Acidic foods like tomatoes, citrus, and pineapple don’t cause canker sores directly, but they irritate existing ones and may trigger new ones in sensitive individuals. Paying attention to what preceded your last few outbreaks can help you identify your personal triggers.
Signs a Canker Sore Needs Medical Attention
Canker sores are occasionally connected to underlying conditions like Crohn’s disease or celiac disease. The American Academy of Oral Medicine recommends seeing your doctor or dentist if you experience more than three outbreaks per month, if you’re never without an ulcer, or if canker sores come with fatigue, abdominal pain, fever, eye discomfort, or rashes elsewhere on your body. A sore that lasts longer than three weeks, grows unusually large, or spreads also warrants a closer look to rule out something beyond a simple canker sore.