Canker sores can’t be “cured” instantly, but several treatments can cut pain significantly and help them heal faster. Most canker sores are small (under 1 cm), heal on their own within one to two weeks, and don’t leave scars. The goal of treatment is to reduce pain, shrink the sore faster, and prevent new ones from forming.
Start Treatment Early for Best Results
The single most important thing you can do is apply a topical treatment as soon as you notice the sore forming. Over-the-counter pastes, gels, and liquids work best when used at the first sign of irritation, before the ulcer fully develops. Products containing benzocaine (sold as Anbesol, Orabase, Zilactin-B) numb the area and create a protective film over the sore. Hydrogen peroxide rinses (like Orajel Antiseptic Mouth Sore Rinse) help keep the area clean and reduce bacteria that can slow healing.
Apply these products directly to the sore, not as a general mouth coating. Reapply after eating or drinking, since food and saliva wash them away quickly.
Home Rinses That Actually Help
A simple saltwater or baking soda rinse is one of the most effective home remedies. Memorial Sloan Kettering Cancer Center recommends mixing 1 teaspoon of salt and 1 teaspoon of baking soda into 4 cups (one quart) of water. You can also use just salt or just baking soda in the same ratio. Swish the rinse gently around the sore for 30 seconds, then spit it out.
Rinse every four to six hours, or more often if the pain is bothering you. This won’t sting like pure salt on a wound because the concentration is low enough to be soothing rather than irritating. The rinse helps keep the ulcer clean and creates a less hospitable environment for bacteria.
Honey Works as Well as Prescription Paste
If you want a natural option, honey is surprisingly effective. A randomized clinical trial compared honey applied directly to canker sores against a standard prescription steroid paste. Both treatments reduced ulcer size by about 60% within a few days, and both achieved complete healing by the final follow-up visit. Pain scores dropped by roughly 48% in both groups during the same period. The results were essentially identical.
To use honey, dab a small amount of raw honey directly onto the sore several times a day, especially after meals and before bed. Let it sit without eating or drinking for a few minutes.
When OTC Products Aren’t Enough
If your canker sore is large, extremely painful, or keeps coming back, a doctor or dentist can prescribe stronger options. A steroid rinse is generally the treatment of choice for more serious or recurring sores. It reduces inflammation and speeds up the healing process in a way that over-the-counter products can’t match.
Chemical cautery treatments (like Debacterol or silver nitrate) are sometimes offered to burn away the sore tissue and provide immediate pain relief. However, research from the University of Iowa’s clinical protocols notes that cautery agents don’t actually alter the course of the disease. They may relieve pain in the moment, but they won’t make the sore heal faster than it would with a steroid rinse.
Some dental offices now offer laser treatment, which targets nerve endings in the sore to provide immediate pain relief and stimulates blood flow to promote tissue repair. Most patients need only one session, and no needles or anesthesia are required.
Nutritional Gaps That Cause Recurring Sores
If you get canker sores frequently, the problem may be nutritional rather than local. Deficiencies in vitamin B12, folate, and iron are strongly linked to recurrent outbreaks. In one study, 73% of patients with B12 deficiency who received B12 therapy recovered completely, and 70% of patients with recurrent canker sores improved with iron and vitamin supplementation.
You don’t need to guess whether you’re deficient. A simple blood test from your doctor can check your levels. If you’re low, targeted supplementation can dramatically reduce how often sores appear. This is especially worth investigating if you get canker sores more than three or four times a year.
What to Avoid While You’re Healing
Acidic foods like tomatoes, citrus fruits, and vinegar-based dressings will make the pain worse and can irritate the tissue further. Spicy foods and rough, crunchy items (chips, crusty bread, raw vegetables) can physically scrape the sore and delay healing. Stick to softer, blander foods until the ulcer closes.
You may have heard that switching to a toothpaste without sodium lauryl sulfate (SLS, the foaming agent in most toothpastes) can prevent canker sores. The evidence on this is mixed. A 2019 review found there wasn’t enough data to confirm that SLS-free toothpaste reduces ulcer frequency, duration, or pain. That said, if you notice your sores tend to appear after brushing, it’s a low-risk change to try.
Canker Sores vs. Cold Sores
These are completely different conditions that require different treatments. Canker sores appear inside the mouth, on the inner cheeks, lips, tongue, or soft palate. They look like single round white or yellow sores with a red border. Cold sores (fever blisters) appear outside the mouth, typically around the border of the lips, and look like clusters of small fluid-filled blisters. Cold sores are caused by the herpes virus and are contagious. Canker sores are not contagious and have no viral cause.
Signs a Canker Sore Needs Medical Attention
Most canker sores are harmless, but the NHS recommends seeing a doctor or dentist if a mouth ulcer lasts longer than three weeks. You should also get it checked if the sore is unusually large, located near the back of your throat, bleeds, or becomes increasingly painful and red, which could signal an infection. A long-lasting mouth ulcer is occasionally a sign of oral cancer, so persistent sores that don’t follow the normal healing pattern are worth having examined.
Canker sores that appear alongside ulcers elsewhere on your body, or with painful, swollen joints, may point to a systemic condition that needs a broader workup.