The best things to put on a canker sore depend on whether you want immediate pain relief or faster healing. Over-the-counter numbing gels containing benzocaine work quickest for pain, while protective pastes and patches shield the sore from further irritation as it heals. Most minor canker sores clear up on their own within two weeks, but the right topical treatment can make those days far more comfortable.
Over-the-Counter Numbing Gels and Pastes
Benzocaine gels (sold as Orajel, Anbesol, and store-brand versions) are the most widely available option. You apply a small amount directly to the sore, and the numbing effect kicks in within a minute or two. It wears off relatively fast, so you may need to reapply several times a day, especially before meals.
Another OTC category worth knowing about is protective pastes. Products containing a mix of a numbing agent and a paste base (like Orabase) stick to the wet tissue inside your mouth and form a temporary coating over the ulcer. This keeps food, drinks, and your teeth from aggravating the sore between applications. The paste works best if you dry the area gently with a tissue before applying it.
Oral Patches and Adhesive Discs
Canker sore patches are thin, dissolvable discs you press directly onto the ulcer. They stick to the moist lining of your mouth and create a physical barrier that protects the wound from friction and contact with acidic or salty foods. Some patches also release a mild pain reliever or anti-inflammatory ingredient gradually over several hours. In lab testing, cellulose-based patches retained their structure for up to 24 hours after absorbing moisture, though real-world wear time is usually shorter because of talking and eating.
Patches tend to work best on sores in easy-to-reach spots, like the inside of your lip or cheek. Sores on the tongue or near the back of the throat are harder to cover effectively.
Saltwater and Baking Soda Rinses
A simple saltwater rinse is one of the oldest and most accessible remedies. Dissolve about half a teaspoon of salt in a cup of warm water, swish it around the sore for 30 seconds, and spit. You can repeat this several times a day. Salt draws fluid out of swollen tissue, which temporarily reduces inflammation and discomfort.
Baking soda rinses work similarly. Use about a teaspoon of baking soda per cup of warm water. Baking soda neutralizes acids in the mouth, which can lower irritation around the ulcer. Some people alternate between salt and baking soda rinses throughout the day. Neither will dramatically speed healing, but both reduce the sting and keep the area cleaner.
Honey
Honey is surprisingly effective. A randomized clinical trial comparing honey applied three times a day to a standard prescription steroid paste found no significant difference between the two in reducing ulcer size, pain, or burning sensation over one week. Honey’s natural anti-inflammatory and wound-healing properties appear to match the prescription option, and the study reported zero side effects in the honey group (while some patients on the steroid paste experienced mild adverse reactions). Use a small dab of plain honey directly on the sore. Manuka honey is often recommended, but the study used regular honey.
Hydrogen Peroxide
A diluted hydrogen peroxide rinse (equal parts 3% hydrogen peroxide and water) can help clean the sore and reduce bacteria around it. You can also dab the diluted solution directly onto the ulcer with a cotton swab. It will fizz and sting briefly. This is more of a cleaning step than a pain treatment, so it pairs well with a numbing gel applied afterward. Avoid swallowing the solution.
Prescription Options for Severe Sores
Most minor canker sores, the kind smaller than a pea, heal within a couple of weeks without any treatment. But sores larger than about one centimeter, or ones that keep coming back, sometimes need something stronger. Major canker sores can take months to heal and often leave scars.
Prescription-strength steroid mouth rinses reduce pain and inflammation when you have multiple sores at once. For individual stubborn ulcers, a doctor or dentist may use chemical cautery, a process that chemically seals the sore’s surface. One cauterizing agent can reduce healing time to roughly a week. Silver nitrate cautery is another option; it hasn’t been shown to speed healing but does help with pain relief.
Oral medications are reserved for the most severe cases, when topical treatments haven’t worked.
Preventing Sores From Coming Back
If you get canker sores frequently, a daily vitamin B12 supplement may help. A double-blind clinical trial tested 1,000 micrograms of sublingual B12 taken at bedtime over six months for people with recurrent canker sores. B12 deficiency is one of several nutritional gaps linked to recurrent outbreaks, along with low iron and folate levels. A blood test can confirm whether you’re deficient, but sublingual B12 at that dose is generally well tolerated even if your levels are normal.
Beyond supplements, pay attention to triggers. Acidic fruits (oranges, tomatoes, pineapple), rough-textured foods like chips, and sodium lauryl sulfate in some toothpastes are common culprits. Switching to an SLS-free toothpaste is one of the simplest changes you can make if sores keep appearing.
What Not to Put on a Canker Sore
Avoid applying undiluted rubbing alcohol, aspirin tablets, or any concentrated essential oil directly to the sore. These can burn the surrounding tissue and make things worse. Full-strength hydrogen peroxide (not diluted to half) is also too harsh. Spicy foods and highly acidic drinks don’t damage the sore permanently, but they will intensify pain significantly while the ulcer is open.
When a Sore Needs a Closer Look
A canker sore that doesn’t improve after two weeks, keeps growing, or comes with a fever warrants a professional evaluation. Persistent, non-healing ulcers in the mouth are considered a red flag for other conditions, including oral cancer. Sores larger than one centimeter, sores that spread in clusters, or sores accompanied by difficulty swallowing all fall outside the range of a typical canker sore and should be examined by a dentist or doctor.