Most mouth ulcers (canker sores) heal on their own within about a week, but you can speed that process and cut the pain significantly with a few simple treatments. The approach depends on whether you’re dealing with a one-off sore or ulcers that keep coming back.
Why Mouth Ulcers Form
Mouth ulcers aren’t infections, and they aren’t contagious. They’re shallow breaks in the lining of your mouth, most often triggered by minor trauma like biting your cheek, a sharp food edge, or an aggressive toothbrush. Stress, hormonal changes, and certain foods (especially acidic or spicy ones) also set them off.
About 70 to 80 percent of people who get mouth ulcers have the minor type, which measures less than 10 mm across and clears up in roughly a week. A smaller group, around 10 percent, develops major ulcers larger than 10 mm. These can take up to four weeks to heal and tend to be considerably more painful. A rare third type, called herpetiform ulcers, appears as clusters of tiny sores that can merge together.
Salt Water Rinses
A salt water rinse is the simplest and most effective first step. Salt doesn’t just “clean” the sore. Research shows that a saline solution actively promotes the migration of cells responsible for wound repair and boosts the production of collagen and other structural proteins your tissue needs to close the wound. The chloride in salt appears to be the key driver of this effect.
The ideal concentration is about one teaspoon (5 grams) of salt dissolved in one cup (250 ml) of warm water. Swish it gently around the ulcer for 30 seconds and spit. Repeat two to three times a day. It will sting briefly, but the healing benefit is real.
Honey as a Topical Treatment
Applying a small amount of honey directly to a mouth ulcer is surprisingly effective. In a clinical trial comparing honey to a standard prescription steroid paste, the honey group saw ulcers shrink and heal in an average of about 2.7 days, compared to nearly 6 days for the steroid group and 7 days for the control group. Honey also outperformed the steroid for pain relief and redness reduction. Multiple studies have confirmed these results.
Use plain, unprocessed honey. Dab a small amount onto the ulcer with a clean finger or cotton swab a few times per day, ideally after eating so it stays in contact with the sore.
Over-the-Counter Options
Pharmacies carry several products designed to coat mouth ulcers and block pain. Protective gels and pastes form a barrier over the sore, shielding it from food and saliva while it heals. Numbing gels containing a local anesthetic can take the edge off pain before meals. Antiseptic mouthwashes help if you’re worried about the area getting irritated by bacteria, though they won’t speed healing as directly as salt water or honey.
For ulcers that are large, very painful, or slow to heal, a doctor or dentist can prescribe a stronger topical steroid paste. In severe or continuous cases, higher-potency preparations or even injections directly into the ulcer may be used to break the cycle.
Check Your Toothpaste
If you get mouth ulcers repeatedly, your toothpaste could be part of the problem. Many common toothpastes contain sodium lauryl sulfate (SLS), a foaming agent that irritates the delicate lining of the mouth. A systematic review of clinical trials found that switching to an SLS-free toothpaste significantly reduced the number of ulcers, the duration of each episode, the overall number of outbreaks, and the level of pain. SLS-free toothpastes are widely available. Check the ingredients list on your current tube.
Nutritional Gaps That Fuel Recurrence
People with recurrent mouth ulcers consistently show lower dietary intake of vitamin B12 and folate compared to people who rarely get them. Iron deficiency is another common finding. These nutrients are essential for maintaining the rapidly dividing cells that line your mouth, so when levels drop, that tissue becomes more vulnerable to breakdown.
You don’t necessarily need supplements. Foods rich in B12 include meat, fish, eggs, and dairy. Folate is abundant in leafy greens, legumes, and fortified grains. If you eat a restricted diet or suspect a deficiency, a simple blood test can confirm it. Studies show that correcting these deficiencies with replacement therapy improves ulcer symptoms and reduces recurrence.
What a Normal Healing Timeline Looks Like
A typical minor mouth ulcer follows a predictable arc. Pain peaks in the first two to three days, then gradually fades. The sore itself closes and disappears within about a week. You may notice a yellowish or grayish center with a red border during the worst of it, which is normal.
Major ulcers are a different story. They’re deeper, wider, and can linger for up to four weeks. They sometimes leave a small scar. If you’re getting ulcers this size or dealing with sores that overlap so you’re never fully healed, that warrants professional treatment rather than home management alone.
Signs That Need Medical Attention
A mouth sore that hasn’t healed after two weeks is the key red flag. Oral cancer can initially look like an ordinary ulcer: a persistent sore, a white or reddish patch, or a lump inside the mouth. Other warning signs include unexplained loose teeth, ear pain, difficulty swallowing, or pain when opening your mouth. Any of these lasting beyond two weeks should be evaluated by a doctor or dentist. This is especially important for people who smoke or drink heavily, as both significantly raise oral cancer risk.