Most canker sores heal on their own within 10 to 14 days, but the right combination of home treatments can cut down pain and speed that timeline. The key is reducing irritation, keeping the ulcer clean, and creating conditions that let the tissue repair faster. Here’s what actually works.
Why Some Canker Sores Last Longer Than Others
The typical canker sore is under a centimeter wide and clears up in about two weeks without treatment. These are minor aphthous ulcers, and they account for the vast majority of cases. Major aphthous ulcers, those larger than a centimeter, can take up to six weeks to heal and sometimes leave a scar. Knowing which type you’re dealing with sets realistic expectations: you can absolutely shorten the painful phase of a minor sore, but a large, deep ulcer may need professional treatment.
Several things slow healing down. Repeatedly biting or brushing the sore, eating acidic or spicy foods, and using toothpaste with sodium lauryl sulfate (SLS) all irritate the open tissue and extend recovery. Removing those irritants is the single fastest thing you can do.
Salt Water and Baking Soda Rinses
Rinsing with salt water or baking soda is the most widely recommended first step. The Mayo Clinic suggests dissolving 1 teaspoon of baking soda in half a cup of warm water. For salt water, a similar ratio works: about half a teaspoon of salt in a cup of warm water. Swish gently for 15 to 30 seconds, then spit. Repeat three to four times a day, especially after meals.
These rinses work by neutralizing acids in your mouth and reducing the bacterial load around the ulcer. They won’t sting the way mouthwash with alcohol will, and they create a cleaner environment for tissue to repair. If you’re only going to do one thing on this list, make it this.
Honey Applied Directly to the Sore
Raw honey has solid evidence behind it for canker sores. A clinical study comparing honey to a standard prescription treatment found that honey significantly reduced ulcer size, pain duration, and the redness surrounding the sore. Honey forms a protective barrier over the ulcer, keeps it moist, and has natural antibacterial and anti-inflammatory properties.
To use it, dab a small amount of raw, unpasteurized honey directly onto the sore three to four times a day. It will dissolve in your mouth, so reapply after eating or drinking. The taste makes this one of the more pleasant remedies, though it can sting briefly on contact.
Over-the-Counter Treatments That Help
Topical gels and pastes containing benzocaine numb the sore on contact and can make eating tolerable within minutes. These are widely available at pharmacies. Apply them directly to the ulcer before meals for the best effect. The numbing is temporary, usually lasting 15 to 30 minutes, but the relief is immediate.
Protective pastes that form a film over the sore are another option. They shield the ulcer from friction and food contact, which both reduces pain and lets healing proceed without repeated irritation. Look for products specifically labeled for mouth ulcers or canker sores. Some contain anti-inflammatory ingredients that may modestly speed recovery.
Antiseptic mouth rinses formulated without alcohol can also help keep the area clean. Avoid any mouthwash that contains alcohol, as it will burn and can further damage the tissue.
What to Eat and What to Avoid
Acidic foods like tomatoes, citrus fruits, and vinegar-based dressings are the biggest offenders. They directly irritate the exposed tissue and can turn a manageable sore into something that throbs for hours. Spicy food does the same. Crunchy items like chips and crackers physically scrape against the ulcer.
Stick to soft, bland, cool foods while the sore is active. Yogurt, smoothies, scrambled eggs, mashed potatoes, and oatmeal are all easy on the mouth. Cold foods like ice pops can also temporarily numb the area and reduce inflammation.
Switch Your Toothpaste
Sodium lauryl sulfate, the foaming agent in most toothpaste, is a known irritant for canker sore sufferers. Switching to an SLS-free toothpaste while you have an active sore reduces the chemical irritation to the ulcer with every brushing. Several major brands sell SLS-free versions. This change won’t heal the sore overnight, but it removes a source of repeated damage that slows recovery.
When brushing, use a soft-bristled toothbrush and be careful around the sore. Physical trauma from brushing is one of the most common reasons a nearly healed canker sore flares back up.
Nutritional Deficiencies and Recurring Sores
If you get canker sores frequently, a nutritional gap may be part of the problem. Deficiencies in vitamin B12, iron, zinc, and folate are all linked to recurrent aphthous ulcers. A clinical trial tested daily sublingual B12 supplements (1,000 mcg) over six months and found it reduced outbreaks in people with recurring sores.
Correcting a deficiency won’t heal the sore you have right now, but it can reduce how often new ones appear. If you’re getting canker sores every few weeks, it’s worth having your levels checked through a simple blood test.
When a Canker Sore Needs Medical Attention
A sore that hasn’t improved after two weeks of home care, or one that’s getting worse, warrants a visit to your doctor or dentist. The same goes for sores that are unusually large, spreading, or accompanied by fever. Prescription options include stronger topical treatments and oral medications that suppress the inflammatory response driving the ulcer.
Persistent mouth ulcers that don’t follow the normal canker sore pattern, especially painless ones or those with irregular borders, should always be evaluated to rule out other conditions.