Most canker sores heal on their own within 10 to 14 days, but you can speed up the process and cut the pain significantly with the right approach. These small, round ulcers inside the mouth are not contagious and not the same thing as cold sores, which appear on the outside of the lips. What you’re dealing with is an irritated patch of soft tissue that responds well to a combination of pain management, gentle oral care, and avoiding the triggers that made it flare up in the first place.
What Actually Works for Pain Relief
The fastest way to knock out canker sore pain is with an over-the-counter numbing gel containing benzocaine. You apply it directly to the sore, and it dulls the nerve endings on contact. The relief is temporary, usually lasting 20 to 30 minutes, but it can make eating and drinking manageable. Reapply before meals for the best effect.
A saltwater rinse is the simplest home treatment. Dissolve about half a teaspoon of salt in a cup of warm water and swish it around your mouth for 30 seconds. This draws fluid out of the swollen tissue and keeps the area clean. It stings at first but tends to calm the sore within a few minutes. You can repeat this several times a day.
Honey applied directly to the sore three times daily has shown real results in clinical studies. In one trial, patients who applied honey to oral ulcers experienced symptom relief faster than those using a saline rinse alone. Another study found honey performed as well as a standard medicated gel at reducing both pain and ulcer size over five days. Use raw honey, dab it on with a clean finger or cotton swab, and try not to eat or drink for a few minutes afterward so it stays in place.
Treatments That Speed Up Healing
If you want the sore gone faster, not just less painful, a few options can actually shorten the healing window. A prescription topical solution called Debacterol works by chemically cauterizing the sore, essentially sealing it off. This can reduce healing time to about a week, compared to the typical two weeks for an untreated sore. Your dentist or doctor applies it in the office, and the process is quick.
Silver nitrate is another chemical cautery option sometimes used in clinical settings. It hasn’t been shown to speed healing, but it can provide meaningful pain relief, which matters when a sore is making it hard to eat, talk, or sleep. For larger or more stubborn sores, prescription steroid gels or pastes reduce the inflammation driving the pain and swelling, helping the tissue repair itself faster.
Over-the-counter protective pastes that form a barrier over the sore can also help. They shield the raw tissue from contact with food, drinks, and your teeth, which prevents the repeated irritation that slows healing down.
Canker Sores vs. Cold Sores
Before you treat anything, make sure you’re dealing with the right problem. Canker sores appear inside the mouth, typically as a single round white or yellow sore with a red border. Cold sores (fever blisters) show up on the outside of the mouth around the lips and look like clusters of small, fluid-filled blisters. Cold sores are caused by a virus and are contagious. Canker sores are neither viral nor contagious. The treatments are completely different, so this distinction matters.
Why You Keep Getting Them
If canker sores are a recurring problem for you, there are a few likely culprits worth investigating.
One common and easy-to-fix trigger is your toothpaste. Many standard toothpastes contain sodium lauryl sulfate (SLS), a foaming agent that can irritate the soft tissue inside your mouth. People prone to canker sores who switch to SLS-free toothpaste tend to get fewer outbreaks, and the sores that do appear are less painful and heal faster. Check the ingredient list on your tube. SLS-free options are widely available.
Nutritional deficiencies play a surprisingly large role. In one study of patients with recurring canker sores, over 50% were deficient in vitamin B12, compared to none in the control group. Low folate levels were also common, appearing in about 46% of patients. If you’re getting canker sores regularly, especially several times a year, it’s worth having your B12, folate, and iron levels checked. Correcting a deficiency can dramatically reduce how often sores appear.
Other known triggers include stress, minor mouth injuries (biting your cheek, aggressive brushing, sharp food like chips), acidic foods such as citrus and tomatoes, and hormonal changes. Keeping a mental note of what happened in the days before a sore shows up can help you identify your personal pattern.
When a Canker Sore Needs Attention
Most canker sores are minor and resolve within two weeks without any lasting effects. Major canker sores, which are larger and deeper, can take up to six weeks to heal and sometimes leave a scar. These are less common but significantly more painful.
A sore that lasts longer than two weeks, keeps coming back in clusters, is unusually large, or comes with a fever deserves a professional look. Persistent ulcers that won’t heal can occasionally signal something other than a simple canker sore, and a dentist or doctor can determine whether further evaluation is needed.