Most canker sores heal on their own within one to two weeks, but the right treatment can cut days off that timeline and significantly reduce pain while you wait. The key is protecting the sore from further irritation, keeping your mouth clean, and choosing the right topical product for your situation.
What a Canker Sore Actually Is
A canker sore is a small, shallow ulcer that forms on the soft tissues inside your mouth: the inner cheeks, gums, tongue, or the floor of your mouth. Unlike cold sores, canker sores aren’t caused by a virus and aren’t contagious. They’re technically called aphthous ulcers, and most people get the minor type, which measures 2 to 5 millimeters across and heals in 4 to 14 days without scarring.
Major canker sores are less common but far more painful. These can grow to 1 to 3 centimeters in diameter, penetrate deeper into the tissue, and last anywhere from 10 days to 6 weeks. A third type, called herpetiform ulcers, shows up as clusters of very small (1 to 2 mm) sores that typically resolve in 7 to 10 days. Knowing which type you’re dealing with helps set realistic expectations for healing.
Over-the-Counter Treatments That Work
The fastest relief comes from topical numbing agents containing benzocaine, which is absorbed rapidly through the mucous membranes in your mouth. You’ll find it in many drugstore products marketed for mouth pain, canker sores, and sore throats. Apply it directly to the sore with a clean finger or cotton swab, and the area goes numb within a minute or two. The effect is temporary, usually lasting 15 to 30 minutes, but it’s enough to eat or drink comfortably.
Protective pastes and gels that coat the sore create a barrier between the ulcer and everything that touches it: food, teeth, your tongue. Look for products with ingredients that form a film over the wound. This shielding effect can reduce pain throughout the day and may speed healing by preventing repeated irritation. Reapply after eating or drinking, since the coating washes away.
Home Remedies Worth Trying
A saltwater rinse is the simplest option. Dissolve about half a teaspoon of salt in a cup of warm water, swish gently for 30 seconds, and spit. This draws fluid out of the swollen tissue, temporarily reduces inflammation, and helps keep the area clean. It will sting for a moment, but the discomfort fades quickly.
Baking soda rinses work similarly and also help neutralize acids in your mouth that can aggravate the sore. The Mayo Clinic recommends dissolving 1 teaspoon of baking soda in half a cup of warm water. You can rinse with this several times a day, especially after meals.
Honey is another option with real evidence behind it. A randomized controlled trial found that honey applied directly to canker sores significantly reduced ulcer size, pain, and redness compared to other treatments. The honey creates a moist, protective layer and has natural properties that support tissue repair. Use a small dab of raw honey directly on the sore a few times daily. It won’t work as fast as a numbing gel for pain, but it may help the sore close up sooner.
Prescription Options for Severe Sores
If over-the-counter products aren’t enough, a dentist or doctor can prescribe a steroid paste designed specifically for mouth ulcers. These work by reducing the inflammatory response in the tissue, which shrinks the sore and relieves pain. You apply the paste directly to the ulcer, and it adheres to the moist surface. If you don’t see improvement within two weeks, your provider will likely want to investigate further.
For particularly painful sores, some clinicians offer in-office cauterization using a chemical agent or laser to destroy the nerve endings on the ulcer’s surface. This provides near-immediate pain relief, though the sore itself still needs time to heal. It’s not a routine treatment, but it’s an option when a canker sore is making it genuinely difficult to eat or talk.
What Triggers Canker Sores
Understanding your triggers is the most effective long-term strategy. Common culprits include biting the inside of your cheek, aggressive tooth brushing, braces or ill-fitting dental appliances, and acidic or spicy foods like citrus, tomatoes, and hot peppers. Stress is another well-documented trigger, which is why many people notice sores appearing during exams, work deadlines, or major life changes.
Nutritional deficiencies play a bigger role than most people realize. Low levels of iron, folate, vitamin B12, vitamin B6, vitamin C, and niacin are all linked to recurrent mouth sores. If you get canker sores frequently, it’s worth having your levels checked with a simple blood test. Correcting a deficiency can dramatically reduce how often sores come back.
Switch Your Toothpaste
One of the easiest and most effective prevention steps is switching to a toothpaste that doesn’t contain sodium lauryl sulfate (SLS), the foaming agent in most commercial toothpastes. A systematic review of clinical trials found that people who used SLS-free toothpaste had significantly fewer ulcers, shorter episodes, less pain, and fewer total outbreaks compared to those using standard toothpaste. The reduction was consistent across all four measures. Check the ingredients list on your tube, and if SLS is listed, try an SLS-free brand for a few months to see if your sores become less frequent.
How to Manage Pain While Healing
Beyond topical treatments, a few daily habits make a noticeable difference. Avoid crunchy foods like chips and crusty bread that can scrape the sore. Eat softer foods at room temperature or slightly cool, since heat intensifies pain. Drink through a straw if the sore is in a spot that liquid hits directly. When brushing your teeth, use a soft-bristled brush and be careful around the affected area.
Ice chips or cold water held against the sore can numb it temporarily without any medication. If overall mouth pain is making meals miserable, an over-the-counter pain reliever taken before eating can help you get through a meal more comfortably.
Signs That Need Medical Attention
Most canker sores are just a nuisance, but certain patterns warrant a visit to your doctor or dentist. The Mayo Clinic flags these specific situations: sores that are unusually large, sores lasting two weeks or more without healing, recurring outbreaks where new sores develop before old ones resolve, sores that extend onto the outer border of your lips, pain you can’t manage with self-care, extreme difficulty eating or drinking, or a high fever accompanying the sores. A sore that won’t heal after two weeks can occasionally signal something other than a simple canker sore, so getting it examined is worthwhile.