Most mouth ulcers heal on their own within one to two weeks without any treatment. But if you’re dealing with one right now, you don’t want to wait. The good news is that a combination of simple rinses, over-the-counter gels, and a few habit changes can cut your pain significantly and speed up healing. For stubborn or severe ulcers, prescription options exist that work on contact.
Why Mouth Ulcers Form
Mouth ulcers (also called canker sores or aphthous ulcers) aren’t caused by one single thing. They result from an immune response triggered by a mix of factors: genetics, stress, hormonal shifts, food sensitivities, infections, and physical injury to the tissue inside your mouth. Biting your cheek, aggressive brushing, or even a sharp edge on a tooth can set one off.
Nutrient gaps play a bigger role than most people realize. In a study of 273 people with recurring mouth ulcers, about 21% were anemic, 20% were low in iron, nearly 5% were deficient in vitamin B12, and about 3% were low in folate. If you get ulcers frequently, it’s worth having your levels checked. Correcting a deficiency can reduce how often they come back.
What Helps Ulcers Heal Faster at Home
Salt and Baking Soda Rinse
The simplest effective treatment is an alkaline saline rinse. Mix 1 teaspoon of table salt and 1 teaspoon of baking soda into 4 cups of warm water. Swish a mouthful gently for 30 to 60 seconds, then spit. This reduces the acidity in your mouth, keeps the area clean, helps prevent infection, and creates a better environment for healing. Doing this three to four times a day, especially after meals, makes eating and talking noticeably more comfortable. St. Jude Children’s Research Hospital recommends this exact formula for patients with mouth sores from cancer treatment, which speaks to how well it works even for severe cases.
Over-the-Counter Pain Relief
Topical gels and pastes you can buy at a pharmacy coat the ulcer and block pain on contact. Most contain a mild pain reliever like menthol or benzocaine. Apply the gel directly to the ulcer after eating and before bed, giving it time to sit without being washed away by food or drink. These products won’t dramatically speed healing, but they make the ulcer far more tolerable while your body does the repair work.
Hydrogen Peroxide Dab
Diluting standard 3% hydrogen peroxide with equal parts water and dabbing it on the ulcer with a cotton swab can help disinfect the area. Limit this to once or twice a day, as overuse can irritate the surrounding tissue.
Foods That Make Ulcers Worse
What you eat during an active ulcer matters more than you might think. Certain foods don’t just cause pain; they can delay healing by repeatedly irritating the open tissue. The main categories to avoid:
- Spicy foods: Hot peppers, sriracha, salsa, curry, chili powder, and crushed red pepper flakes. The capsaicin in these directly irritates the sore.
- Acidic foods and drinks: Citrus fruits, tomatoes, berries, pineapple, vinegar, coffee, alcohol, and fruit juice. These create a stinging or burning sensation and can slow the healing process.
- Hard or crunchy foods: Granola, pretzels, crusty bread, popcorn, potato chips, and crackers. These scrape against the ulcer and reopen healing tissue.
- Hot-temperature foods: Let soups, drinks, and cooked dishes cool before eating. Heat amplifies pain at the ulcer site.
Stick to soft, cool, or room-temperature foods while the ulcer is active. Yogurt, scrambled eggs, mashed potatoes, smoothies, and oatmeal are all easy options that won’t aggravate the area.
When to Consider Prescription Treatment
If you get large ulcers, clusters of ulcers, or outbreaks that keep coming back, a dentist or doctor can prescribe steroid mouth rinses that are far more powerful than anything available over the counter. These typically involve swishing a small amount of medicated liquid for about one minute after meals and before bed, then spitting it out. The key instruction is to avoid eating or drinking for at least 30 minutes afterward so the medication stays in contact with the tissue long enough to work.
These prescription rinses reduce inflammation directly at the ulcer site and can shorten healing time considerably. For the most severe cases, your provider may combine the steroid with an antifungal agent, since long-term steroid use in the mouth can sometimes encourage yeast overgrowth.
Laser treatment is another option gaining traction. A systematic review found that low-level laser therapy significantly reduced ulcer pain immediately and over the first three days, while also shortening overall healing time. It’s typically done in a single session at a dental office and is painless. Not every dental practice offers it, but it’s worth asking about if your ulcers are severe or frequent.
Preventing Ulcers From Coming Back
Switch Your Toothpaste
Many mainstream toothpastes contain sodium lauryl sulfate (SLS), a foaming agent that can irritate the lining of your mouth. Some research has reported up to a 70% reduction in ulcers among people who switched to SLS-free toothpaste. A more rigorous double-blind trial found that SLS-free toothpaste didn’t reduce the total number of ulcers, but participants reported less pain and slightly faster healing while using it. If you get ulcers regularly, trying an SLS-free option for a couple of months is a low-risk experiment. Brands like Sensodyne, Biotene, and certain Toms of Maine formulas are SLS-free.
Address Nutritional Gaps
Given how common iron, B12, and folate deficiencies are among people with recurring ulcers, eating more leafy greens, red meat, eggs, fortified cereals, and legumes can help. If dietary changes aren’t enough, a simple blood test can identify whether a supplement would be beneficial.
Reduce Mechanical Triggers
Use a soft-bristled toothbrush. If you have braces, retainers, or dentures that rub against your cheeks or gums, orthodontic wax can create a buffer. Be mindful of biting the inside of your cheeks or lips, which is a common unconscious habit, especially during stress.
Minor vs. Major Ulcers
Most mouth ulcers are classified as minor. They’re smaller than 1 centimeter across, shallow, and located on the inner cheeks, lips, soft palate, or floor of the mouth. These typically heal within one to two weeks without scarring.
Major ulcers are larger, deeper, and significantly more painful. They can take weeks or even months to fully resolve and sometimes leave scars. If you develop an ulcer that’s unusually large or deep, prescription treatment is worth pursuing rather than waiting it out.
A third, less common type called herpetiform ulcers appears as clusters of tiny pinpoint sores that can merge together. Despite the name, these aren’t caused by the herpes virus.
Ulcers That Don’t Heal
A standard mouth ulcer should show clear improvement within two weeks. If an ulcer persists beyond three to four weeks, a healthcare provider will likely recommend a biopsy to rule out oral cancer or other conditions. Other warning signs include an ulcer that keeps growing, one that’s completely painless (most canker sores hurt), or ulcers accompanied by fever, difficulty swallowing, or new ulcers appearing before old ones heal. Recurring ulcers can also be a sign of celiac disease, Crohn’s disease, or an autoimmune condition, so frequent outbreaks are worth investigating beyond just treating the symptoms.