Most canker sores heal on their own within 10 to 14 days, but the right treatments can cut pain dramatically and speed up that timeline. There’s no single overnight cure, but a combination of topical relief, simple home remedies, and trigger avoidance can make a real difference in how fast you recover and how often sores come back.
What Actually Heals a Canker Sore
Canker sores (aphthous ulcers) are shallow, open wounds on the soft tissue inside your mouth. Unlike cold sores, they aren’t caused by a virus and aren’t contagious. Minor canker sores, the most common type, typically resolve in 10 to 14 days without treatment. Major canker sores, which are deeper and larger, can take up to a month.
The goal of treatment is twofold: relieve pain so you can eat and talk normally, and protect the sore so it heals faster. Most approaches work by doing one or both of those things.
Over-the-Counter Options That Work
The fastest relief comes from topical products containing benzocaine at 20%, which numbs the area on contact. You’ll find this in gels and liquids marketed specifically for canker sores. Apply it directly to the sore with a cotton swab before meals or whenever pain flares up. The numbing effect is temporary, lasting roughly 20 to 30 minutes, but it makes eating much more tolerable.
Protective pastes that form a barrier over the sore are another solid option. These stick to the wet tissue inside your mouth and shield the ulcer from food, drinks, and your teeth. Look for products labeled as oral wound care or canker sore patches. The physical barrier alone can reduce irritation enough to let healing happen faster.
Antimicrobial mouth rinses containing hydrogen peroxide (diluted) can also help keep the area clean and prevent a secondary infection from slowing things down. Swish gently and spit; don’t swallow.
Home Remedies Worth Trying
Honey stands out among home remedies because it has actual clinical evidence behind it. A randomized controlled trial of 94 people with minor canker sores compared honey applied four times daily for five days against a topical steroid and a protective paste. The honey group saw significantly faster reduction in ulcer size, fewer days of pain, and less redness than both other groups, with no side effects reported. Raw, unprocessed honey applied directly to the sore is what was studied.
A saltwater rinse is the simplest option you probably already have at home. Dissolve about half a teaspoon of salt in a cup of warm water and swish for 30 seconds. It stings initially but helps clean the sore and can reduce inflammation. You can do this several times a day.
Baking soda rinses work similarly. Mix one teaspoon in half a cup of warm water, swish, and spit. Baking soda helps neutralize acids in your mouth that irritate the ulcer.
When Sores Keep Coming Back
If you get canker sores frequently, the cause may be nutritional. Research has found a surprisingly high rate of iron, folate, and B vitamin deficiencies among people with recurring canker sores. Correcting those deficiencies has been shown to reduce or eliminate recurrences in most cases. One double-blind study found that vitamin B12 supplements prevented canker sore recurrences even in people whose B12 levels were normal. If you’re dealing with chronic sores, a blood test checking your iron, B12, and folate levels is a practical first step.
Your toothpaste could also be a factor. A systematic review of clinical trials found that toothpaste free of sodium lauryl sulfate (SLS), a common foaming agent, significantly reduced the number of ulcers, the duration of each sore, the number of outbreaks, and pain levels compared to regular SLS-containing toothpaste. The reduction averaged about one fewer ulcer per cycle and nearly two fewer days of symptoms. Several brands now sell SLS-free formulas, and switching is one of the easiest changes you can make.
Common Triggers to Avoid
While a sore is active, acidic foods like citrus, tomatoes, and vinegar-based dressings will make pain worse and can slow healing. Spicy foods and anything with sharp or rough edges (chips, crusty bread, hard pretzels) physically irritate the ulcer.
Beyond food, pay attention to patterns. Stress is one of the most well-documented triggers. Accidental bites to the inside of your cheek, aggressive tooth brushing, and orthodontic hardware rubbing against tissue are all common mechanical causes. If you notice sores appearing after eating certain foods like chocolate, coffee, nuts, or wheat, you may have a sensitivity worth tracking.
Prescription Treatments for Severe Cases
For large or especially painful sores, a doctor can prescribe a steroid rinse that reduces inflammation more aggressively than anything available over the counter. These rinses are swished around the mouth and spit out. The main thing to be aware of is that steroid rinses can sometimes lead to a secondary fungal infection in the mouth, so they’re typically used for short courses.
For targeted pain relief, prescription-strength numbing gel applied with a cotton swab several times a day can make severe sores manageable. This is stronger than what you’d find at a pharmacy and lasts longer per application.
Some dental offices now offer low-level laser treatment for canker sores. A single 30-second laser exposure has been shown to bring dramatic results: 73% of patients reported zero pain within 24 hours, and 88% of treated sores healed to a comfortable, resurfaced state within two days. Untreated sores in the same study took five to ten days to reach the same point. If you have access to a dentist who offers this, it’s worth asking about for particularly bad or poorly timed sores.
Signs a Canker Sore Needs Medical Attention
Most canker sores are harmless, but certain patterns warrant a closer look. A sore that lasts longer than two weeks without healing, sores that are unusually large, or new sores that develop before old ones have healed all justify a visit to your doctor or dentist. The same goes for sores that extend onto the outer lip border, pain you can’t manage with the approaches above, difficulty eating or drinking enough, or a high fever accompanying the sores. These can sometimes signal an underlying condition like celiac disease, an immune disorder, or Behçet’s disease that needs its own treatment.