Most canker sores heal on their own within one to two weeks, but the right combination of home care and over-the-counter products can cut pain significantly and speed that timeline. The key is starting treatment early, as soon as you feel that telltale tingling or spot the sore forming.
What You’re Dealing With
Canker sores (aphthous ulcers) are small, shallow ulcers that form on the soft tissues inside your mouth: the inner lips, cheeks, tongue, soft palate, or floor of the mouth. They’re not contagious and not the same as cold sores, which appear on the outside of the lips. Most are “minor” canker sores, less than 1 cm across, and heal without scarring. Larger, deeper ones (called major aphthae) can take weeks longer and sometimes leave a scar.
Saltwater and Hydrogen Peroxide Rinses
The simplest thing you can do right now is rinse with warm saltwater a few times a day. Dissolve about half a teaspoon of salt in a cup of warm water, swish for 30 seconds, and spit. This draws fluid out of the swollen tissue and helps keep the area clean.
A hydrogen peroxide rinse is another option. Mix equal parts water and standard 3% hydrogen peroxide, dab it onto the sore with a cotton swab (don’t swallow it), then follow with a small amount of milk of magnesia on the spot. The peroxide disinfects the surface while the milk of magnesia coats and soothes it.
Honey Works as Well as Prescription Paste
If you want something more active than saltwater, raw honey is worth trying. A randomized clinical trial compared applying half a milliliter of honey three times a day to using a prescription steroid paste (triamcinolone acetonide) on the same schedule. Both groups saw their ulcers shrink by about 60% within the first few days, and both reached complete healing on the same timeline. Pain scores dropped at nearly identical rates. The one area where honey performed better was burning sensation: honey reduced it by 55% at the first follow-up compared to 30% for the steroid paste, a statistically significant difference. None of the honey users experienced side effects, while 10% of the steroid group reported itching and redness that lasted even after healing.
To use this approach, dab a small amount of honey directly onto the sore three times a day, ideally after meals so it stays in place longer.
Over-the-Counter Pain Relief
For immediate pain control, look for topical numbing gels containing benzocaine, sold under brand names like Orajel and Anbesol. These temporarily deaden the nerve endings around the sore so you can eat and talk more comfortably. Apply with a clean finger or cotton swab as directed on the label.
Alcohol-free mouth rinses can also help. Rinses that contain alcohol tend to sting and may irritate the sore further, so check the label before you buy. Some medicated rinses designed specifically for mouth sores contain mild anti-inflammatory or antiseptic ingredients that create a protective film over the ulcer.
Chemical Cautery for Stubborn Sores
If a sore is large or unusually painful, your dentist or doctor can apply a chemical cautery agent directly to it. One product, Debacterol, chemically seals the sore and can reduce healing time to about a week. Silver nitrate is another cautery option; it hasn’t been shown to speed healing, but it reliably reduces pain. Both procedures take only a moment in the office and provide fast relief because they essentially destroy the exposed nerve endings in the ulcer.
Switch to SLS-Free Toothpaste
This is one of the highest-impact changes you can make if you get canker sores repeatedly. Most toothpastes contain sodium lauryl sulfate (SLS), a foaming agent that also happens to be a well-documented irritant to the lining of the mouth. A systematic review published by the American Dental Association pooled data from multiple trials and found that switching to an SLS-free toothpaste produced statistically significant reductions across the board: fewer ulcers, shorter ulcer duration, fewer recurring episodes, and less pain. One pooled analysis showed an average reduction of about one ulcer per episode, while another showed a reduction of roughly four ulcers over the study period.
SLS-free toothpastes are easy to find. Brands like Sensodyne, Biotene, and certain Arm & Hammer varieties skip this ingredient. Check the back of the tube for “sodium lauryl sulfate” in the inactive ingredients list.
Check for Nutritional Gaps
Recurrent canker sores are linked to low levels of iron, vitamin B12, folic acid, and zinc. You don’t necessarily need supplements if your diet already covers these nutrients, but if you notice sores coming back frequently, it’s worth looking at what you eat. Iron comes from red meat, lentils, and spinach. B12 is found in animal products and fortified cereals. Folate is abundant in leafy greens, beans, and citrus. Zinc shows up in meat, shellfish, seeds, and nuts.
If you suspect a deficiency, particularly if you follow a vegan or restrictive diet, a simple blood test can confirm whether supplementation would help.
Common Triggers to Avoid
Beyond SLS, several everyday factors can set off canker sores or make existing ones worse:
- Acidic and spicy foods. Citrus fruits, tomatoes, hot peppers, and vinegar-based dressings all irritate open tissue inside the mouth.
- Mechanical trauma. Biting your cheek, aggressive brushing, braces, or ill-fitting dentures can damage the lining and trigger a sore.
- Stress. Outbreaks commonly cluster around stressful periods, likely because stress affects immune function.
- Hormonal shifts. Some people notice sores appearing at specific points in their menstrual cycle.
Keeping a simple log of when sores appear and what was happening in the days before can help you identify your personal triggers.
When Canker Sores Need Professional Attention
Most canker sores resolve within two weeks. If a sore lasts longer than that, it warrants a professional look. Oral lesions that persist beyond two weeks after any obvious irritant is removed are generally recommended for biopsy to rule out other conditions, including oral cancer. You should also see a provider if a sore is unusually large, spreading, accompanied by fever, or making it too painful to drink enough fluids. Recurrent outbreaks, especially several times a year, can sometimes point to an underlying condition like celiac disease or an immune disorder that’s worth investigating.