Most canker sores heal on their own within 4 to 14 days, but the right care can cut that timeline significantly. The key is reducing irritation, managing pain so you can eat and drink normally, and creating conditions that let the tissue repair itself. A few evidence-backed approaches, from honey to SLS-free toothpaste, can make a real difference.
How Long Canker Sores Normally Take to Heal
Minor canker sores, the most common type, are usually 2 to 5 millimeters across and resolve within one to two weeks without treatment. Major canker sores (1 to 3 centimeters, roughly pea-sized or larger) can last anywhere from 10 days to 6 weeks and sometimes leave scars. Knowing which type you’re dealing with helps set realistic expectations: if your sore is small, you’re looking at shaving a few days off a one- to two-week process. If it’s large and deep, healing will take longer no matter what you do, and a doctor visit is worthwhile.
Apply Honey Directly to the Sore
Plain honey is one of the most effective home treatments available, and it outperforms some clinical options. In a randomized controlled trial, honey reduced ulcer size and healed sores in an average of about 2.7 days, compared to nearly 6 days for a prescription steroid paste and 7 days for a protective oral base alone. That’s not a small margin.
To use it, dab a small amount of raw honey directly onto the sore three to four times a day, especially after meals and before bed. Honey has natural antibacterial and anti-inflammatory properties, and it forms a protective layer over the exposed tissue. Manuka honey is a popular choice, but regular raw honey showed results in the clinical trial. Avoid licking it off immediately; let it sit for a few minutes.
Over-the-Counter Pain Relief
Benzocaine gels and ointments are the most widely available OTC option for canker sore pain. They numb the area on contact, making it easier to eat, drink, and brush your teeth without wincing. Apply a small amount directly to the sore up to four times a day. Benzocaine comes in gels, sprays, pastes, and lozenges, so you can pick the format that’s easiest for you.
Pain relief doesn’t directly speed healing, but it matters more than people think. When a sore hurts too much to brush properly or eat a balanced diet, you create conditions that slow recovery. Keeping the area clean and staying nourished both support faster tissue repair.
Try Alum Powder for Stubborn Sores
Alum powder (potassium aluminum sulfate), found in the spice aisle of most grocery stores, works by contracting the tissue and reducing swelling. It tightens the proteins in the sore’s surface, which strengthens capillary walls and limits the leaking of fluid into surrounding tissue. It also lowers the local pH enough to discourage bacterial growth.
To apply it, dampen a clean fingertip, dip it in a small amount of alum powder, and press it onto the sore for about 10 minutes. Do this three times a day for up to five days. It will sting initially, sometimes intensely, but the sore typically shrinks noticeably within a day or two. Rinse your mouth afterward.
Saltwater and Baking Soda Rinses
A simple rinse of half a teaspoon of salt in a cup of warm water is one of the oldest and most practical canker sore treatments. Salt draws fluid out of inflamed tissue, reducing swelling and creating an environment that’s less hospitable to bacteria. Swish for 30 seconds and spit. You can do this several times a day, especially after eating.
Baking soda rinses work similarly by neutralizing acids in the mouth that irritate the sore. Dissolve a teaspoon of baking soda in half a cup of warm water and swish. This is especially useful if you’ve just eaten something acidic.
Switch to SLS-Free Toothpaste
Sodium lauryl sulfate (SLS) is the foaming agent in most toothpastes, and it’s a known irritant for people prone to canker sores. A meta-analysis of crossover trials found that switching to an SLS-free toothpaste significantly reduced the number of ulcers, the duration of each episode, the frequency of outbreaks, and pain levels across all four measures studied.
If you get canker sores more than once or twice a year, this is one of the simplest long-term changes you can make. Several brands sell SLS-free formulas, often marketed for sensitive mouths. The switch won’t heal a current sore overnight, but it can prevent the next one and reduce irritation to the one you have now.
Foods That Help and Hurt
Acidic foods and drinks are the biggest dietary culprits. Citrus fruits, alcohol, fizzy drinks, tomatoes, and strawberries all lower the pH in your mouth, which disrupts the protective lining and irritates exposed tissue. Spicy and salty foods do the same through direct chemical irritation. While you have an active sore, avoiding these can prevent setbacks in healing.
Soft, cool, bland foods are your best options: yogurt, oatmeal, mashed potatoes, smoothies, scrambled eggs. Cold foods can also provide mild pain relief. Drinking through a straw helps liquids bypass the sore, especially if it’s on the inner lip or front of the mouth.
Check for Nutritional Deficiencies
People who get canker sores repeatedly often have lower levels of vitamin B12 and folate. In one study, people with recurrent sores consumed about 7% less B12 and 20% less folate per day than people without sores. Iron deficiency has also been linked to frequent outbreaks. Correcting these deficiencies through diet or supplements has been shown to reduce the frequency and severity of future episodes.
Good dietary sources of B12 include meat, fish, eggs, and dairy. Folate is abundant in leafy greens, legumes, and fortified grains. If you get canker sores several times a year and your diet is limited in any of these areas, a basic blood panel from your doctor can identify whether a deficiency is contributing. Supplementation in deficient patients consistently improves outcomes.
Signs a Canker Sore Needs Medical Attention
Most canker sores are harmless and self-limiting, but some warrant a call to your doctor or dentist. Seek care if a sore lasts longer than two weeks, is larger than a centimeter (bigger than a pea), comes with fever or flu-like symptoms, recurs two or three times a year, or interferes with eating and drinking to the point where you’re not getting adequate nutrition. Large or persistent sores sometimes need prescription-strength treatment, and in rare cases, a non-healing mouth ulcer can signal something other than a canker sore entirely.