Most canker sores heal on their own within one to two weeks, but you don’t have to wait it out in pain. A combination of simple rinses, over-the-counter products, and a few habit changes can cut the discomfort significantly and may speed healing. Here’s what actually works.
Saltwater and Baking Soda Rinses
The simplest and cheapest treatment is one you can make at home right now. Mix 1 teaspoon of salt and 1 teaspoon of baking soda into 1 quart (4 cups) of water. Swish the solution gently around your mouth for 30 seconds, then spit. You can repeat this every four to six hours, or more often if the pain flares up. If you only have salt or only have baking soda, either one works on its own in the same ratio of 1 teaspoon per quart of water.
The salt draws fluid out of the inflamed tissue, which reduces swelling. Baking soda neutralizes acids in your mouth that irritate the open sore. Neither will sting as much as you might expect, and they’re safe to use as often as you need.
Over-the-Counter Products That Help
If rinses alone aren’t enough, look for OTC pastes, gels, or liquids designed for mouth sores. The key active ingredients to look for are benzocaine, which numbs the area on contact, and hydrogen peroxide, which acts as an antiseptic. Products like Anbesol, Orabase, and Orajel Antiseptic Mouth Sore Rinse contain these ingredients. Apply them directly to the sore as soon as it appears for the best results.
Protective pastes that form a barrier over the ulcer can be especially useful before meals, since they keep food and drink from hitting the raw surface. Timing matters: the earlier you start treatment after a sore develops, the more effective these products tend to be.
What to Eat and Avoid
Acidic foods like tomatoes, citrus fruits, and vinegar-based dressings will make the pain noticeably worse. Spicy food, crunchy chips, and anything with sharp edges (think tortilla chips or crusty bread) can physically scrape the sore and delay healing. Stick with softer, blander foods while the sore is active. Yogurt, oatmeal, scrambled eggs, and smoothies are all easy choices.
Temperature matters too. Very hot coffee or soup can aggravate the sore, so let things cool down before eating or drinking.
When Canker Sores Keep Coming Back
If you get canker sores frequently, the cause may go deeper than a one-time mouth injury. Deficiencies in vitamin B12, folate, iron, and zinc are all linked to recurrent mouth ulcers. You don’t need to start supplementing blindly, but if sores keep returning, a blood test can reveal whether a nutritional gap is driving them.
Your toothpaste could also be a factor. Many toothpastes contain sodium lauryl sulfate (SLS), a foaming agent that can irritate the lining of your mouth. People prone to canker sores often see fewer outbreaks after switching to an SLS-free toothpaste. Several major brands now make SLS-free versions, so this is an easy change to try.
Stress is another well-established trigger. You may notice sores cropping up during high-pressure weeks at work or after poor sleep. That pattern is real, not coincidental.
Three Types of Canker Sores
Not all canker sores are the same size or severity. Minor canker sores, the most common type, are small (under 1 cm across), shallow, and oval-shaped. These are the ones that typically clear up within a week or two without scarring.
Major canker sores are larger, deeper, and considerably more painful. They can take weeks to heal and sometimes leave scars. Herpetiform canker sores are a third, less common type that appear as clusters of many tiny ulcers. Despite the name, they have nothing to do with the herpes virus.
Prescription Options for Severe Cases
If your sores are large, extremely painful, or keep interfering with eating and drinking, a doctor or dentist can prescribe stronger treatments. These typically involve prescription-strength anti-inflammatory rinses or ointments that reduce swelling and pain more aggressively than anything available over the counter. For a single stubborn sore that won’t respond to other treatments, a provider may use a chemical cauterizing agent to essentially seal the ulcer surface. This doesn’t change the course of the disease, but it can provide immediate pain relief.
Prescription treatment is generally reserved for sores that are larger than a centimeter, sores that have lasted more than two weeks, or cases where outbreaks happen multiple times a year.
Signs a Canker Sore Needs Medical Attention
A sore that lasts longer than two weeks is the clearest signal to get it checked. Other reasons to contact a healthcare provider include sores bigger than a centimeter (roughly the size of a pea), sores accompanied by fever or flu-like symptoms, outbreaks that happen two or three times a year, and sores so painful they interfere with eating, drinking, or talking. In these cases, your provider may want to run tests to confirm the sore is actually a canker sore and not something else that needs different treatment.