Most canker sores heal on their own within a few weeks, but you don’t have to wait it out in pain. A combination of over-the-counter products, simple home care, and avoiding known triggers can speed healing and cut days off your discomfort. For stubborn or severe sores, prescription options and in-office treatments exist that work even faster.
What a Canker Sore Actually Is
Canker sores are small, round ulcers that form inside your mouth, typically on the inner lips, cheeks, or tongue. They’re usually white or yellow with a red border. Unlike cold sores, which are caused by the herpes virus and appear outside the mouth around the lips, canker sores are not contagious and occur only on the inside.
There are three types, and the type you have determines how long you’ll be dealing with it. Minor canker sores, the most common kind, are smaller than a pea and heal within a few weeks without scarring. Major canker sores are larger than one centimeter, extremely painful, and can take months to heal, often leaving scars. Herpetiform canker sores are rare clusters of tiny pinpoint sores that typically resolve within about two weeks.
Over-the-Counter Pain Relief
The fastest way to get relief right now is a topical numbing product containing benzocaine. These come as gels, pastes, and liquids that you apply directly to the sore. Benzocaine is a local anesthetic that numbs the area on contact, making it easier to eat, drink, and get through your day. You’ll find it in most canker sore products at any pharmacy. Reapply as directed on the label, since the numbing effect is temporary.
Over-the-counter protective pastes can also help by forming a barrier over the sore, shielding it from food, drinks, and your teeth. This reduces irritation and gives the tissue underneath a chance to heal faster.
Home Remedies That Help
Salt water rinses are one of the oldest and simplest treatments. Dissolve about half a teaspoon of salt in a cup of warm water and swish it around your mouth for 30 seconds before spitting it out. Salt draws fluid from the tissue, which can reduce swelling and create a less hospitable environment for bacteria. You can repeat this several times a day.
Baking soda rinses work similarly. Mix one teaspoon of baking soda in half a cup of warm water and rinse. This helps neutralize acids in your mouth that irritate the sore. Holding a small ice chip against the sore can also temporarily dull the pain.
While you’re healing, avoid acidic and spicy foods like citrus fruits, tomatoes, and hot peppers. These won’t slow healing directly, but they’ll make the pain significantly worse. Switching to a soft-bristled toothbrush and using a toothpaste free of sodium lauryl sulfate (a foaming agent that can irritate mouth tissue) may also help prevent new sores from forming.
When to Try Prescription Treatments
If you get canker sores frequently or they’re large and slow to heal, a doctor or dentist can prescribe stronger options. A medicated mouth rinse containing a steroid like dexamethasone reduces both pain and inflammation. Some prescription rinses contain lidocaine, a stronger numbing agent than what’s available over the counter. For severe cases that don’t respond to rinses, oral steroid medications are sometimes used as a last resort due to their potential side effects.
In-Office Cauterization
One of the most effective treatments for a painful canker sore is chemical cauterization with silver nitrate, done in a dentist’s or doctor’s office. A small applicator stick is touched to the sore, which destroys the damaged surface tissue and promotes faster healing underneath.
The results are impressive. In one clinical study, 60% of patients treated with silver nitrate had fully healed ulcers by day seven, compared to just 32% in the placebo group. Patients who healed reported an average healing time of only 2.7 days after the procedure. Pain scores were also significantly lower starting from the first day. Another study found silver nitrate provided pain relief in just over one day on average, compared to nearly five days for placebo. No side effects were reported in either study.
If you have a major canker sore or one in a spot that makes eating miserable, asking your dentist about cauterization is worth it.
Nutritional Gaps That Cause Recurring Sores
If canker sores keep coming back, your body may be low on certain nutrients. Deficiencies in vitamin B12, iron, and folic acid are all linked to more frequent outbreaks. You don’t necessarily need supplements right away. A blood test from your doctor can check your levels. If a deficiency shows up, correcting it through diet or supplementation often reduces how often sores appear.
Good dietary sources of these nutrients include red meat, eggs, and dairy for B12; leafy greens, beans, and fortified cereals for folic acid; and red meat, lentils, and spinach for iron.
Common Triggers to Avoid
Canker sores can be triggered by physical irritation, stress, hormonal changes, and certain foods. Sharp tooth edges, braces, and ill-fitting dental appliances are common culprits. If you notice sores appearing after dental work or near a rough tooth, see your dentist to have the surface smoothed or the appliance adjusted.
Stress is another well-known trigger, and many people notice outbreaks during high-pressure periods at work or school. While you can’t always eliminate stress, recognizing the pattern helps you start treatment early. Some people also find that specific foods, particularly acidic fruits, chocolate, and coffee, seem to trigger their sores. Keeping a simple food diary when outbreaks occur can help you identify your personal triggers.
Signs a Canker Sore Needs Medical Attention
Most canker sores are harmless annoyances, but certain patterns warrant a visit to your doctor or dentist. Watch for sores that are unusually large, sores lasting longer than two weeks, recurring outbreaks where new sores develop before old ones heal, sores that extend to the outer lip border, pain you can’t manage with over-the-counter products, difficulty eating or drinking, or a high fever alongside the sores. A sore that doesn’t heal could occasionally signal something other than a simple canker sore, and your doctor may want to take a closer look or run tests.