Most mouth ulcers heal on their own within a few days to two weeks, but the right treatment can cut pain significantly and speed recovery. What works best depends on the size of the ulcer, how much it hurts, and whether it keeps coming back. Here’s what actually helps, from simple home care to stronger options.
How Long Mouth Ulcers Take to Heal
Not all mouth ulcers are the same, and the timeline varies quite a bit. Mild ulcers, the kind most people get a few times a year, are minimally painful and typically resolve in two to three days without any treatment. More painful episodes can last up to 10 days.
About 10% of people who get recurring ulcers develop major ones, larger than 1 cm across. These can take up to six weeks to heal and sometimes leave a scar. If your ulcer falls into this category, over-the-counter remedies alone may not be enough.
Home Remedies That Work
Honey applied directly to the ulcer is one of the best-supported home treatments. Clinical research on mouth sores from cancer treatment found that honey reduced the onset of moderate to severe inflammation by 75% compared to standard care. For a simple canker sore, dab a small amount of raw honey onto the ulcer a few times a day, especially before bed. It forms a protective coating and has natural antibacterial properties.
A saltwater rinse is the simplest option: dissolve half a teaspoon of salt in a cup of warm water and swish gently for 30 seconds. It stings briefly but helps clean the area. You can also dilute 3% hydrogen peroxide with an equal amount of water and apply it directly to the ulcer or use it as a rinse. This helps keep the sore clean without damaging the surrounding tissue.
Over-the-Counter Pain Relief
For ulcers that make eating or talking painful, a topical numbing gel containing benzocaine (sold in concentrations between 5% and 20%) provides fast, temporary relief. You apply it directly to the sore before meals or whenever the pain is worst. The effect wears off within an hour or so, but it makes a real difference during flare-ups.
Protective pastes and patches that cover the ulcer are another option. These create a physical barrier between the sore and your food, teeth, and tongue. They won’t speed healing much, but they reduce irritation throughout the day. Look for products labeled specifically for mouth ulcers or canker sores at any pharmacy.
Prescription Options for Severe Ulcers
If over-the-counter treatments aren’t enough, a dentist or doctor can prescribe a steroid dental paste. The most common one is applied at bedtime so the medication stays in contact with the ulcer overnight. For more severe cases, you may need to apply it two or three times a day, ideally after meals. If you don’t see improvement within two weeks, your provider will likely want to reassess.
For widespread or extremely painful sores, providers sometimes prescribe a compounded medicated mouthwash, often called “magic mouthwash.” Every formula is custom-made for the patient, so there’s no standard recipe you can mix at home. The typical instructions are to shake the bottle, measure the prescribed amount, swish it around your mouth to coat all surfaces, then spit it out. You should avoid eating or drinking for 30 minutes afterward. If the rinse contains a numbing ingredient, skip hot beverages, since you may not feel a burn.
Foods to Avoid While Healing
What you eat matters more than most people realize. Acidic foods like oranges, lemons, grapefruits, tomatoes, and vinegar-based dressings cause a sharp sting on contact and can slow healing. Spicy foods with chili peppers or hot sauce irritate the exposed tissue and create a burning sensation that lingers after you finish eating.
Hard, crunchy foods are a problem too. Chips, crackers, crusty bread, and nuts can scrape against the ulcer, reopening it or making it worse. Even if the initial contact doesn’t hurt much, repeated friction delays recovery. Very salty or processed foods draw moisture from the tissue and intensify pain. Alcohol dries out the mouth and slows healing. Carbonated drinks irritate through both their fizz and their acidity. Hot beverages, including coffee and tea, increase blood flow to the area and can make pain worse after the initial sip.
Stick to soft, cool, or room-temperature foods while the ulcer heals. Yogurt, smoothies, scrambled eggs, and mashed potatoes are all easy choices.
Preventing Ulcers From Coming Back
If you get mouth ulcers regularly, switching your toothpaste is one of the simplest changes you can make. Many toothpastes contain sodium lauryl sulfate (SLS), a foaming agent that irritates the lining of the mouth. A meta-analysis found that people using SLS-free toothpaste developed roughly one fewer ulcer per episode compared to those using standard toothpaste. Several brands now market SLS-free options, and they’re widely available.
Vitamin B12 supplementation has strong evidence behind it. A randomized, double-blind trial published in the Journal of the American Board of Family Medicine gave participants 1,000 mcg of sublingual B12 daily for six months. The supplement significantly reduced ulcer recurrence regardless of whether participants had a B12 deficiency to begin with. The tablets were taken once daily before bed. This is worth trying if you deal with canker sores more than a few times a year.
Other common triggers include stress, hormonal changes, and minor mouth injuries from biting your cheek or brushing too aggressively. A soft-bristled toothbrush and gentler brushing technique can help if you tend to get ulcers in spots where the brush hits hard.
When an Ulcer Needs Professional Attention
Any single mouth ulcer that lasts longer than three weeks despite treatment should be examined by a dentist or doctor. At that point, a specialist referral and possible biopsy may be recommended to rule out other conditions, including oral cancer. The same applies if your ulcers are unusually large, spreading, accompanied by fever, or making it difficult to drink enough fluids. Recurring ulcers that come in clusters or appear more than a few times a year also warrant a closer look, since they can sometimes signal an underlying nutritional deficiency or immune system issue.