Most canker sores on your gums heal on their own within one to two weeks, but the right treatments can cut down pain significantly and speed up that timeline. These small white or yellow ulcers aren’t contagious and aren’t caused by a virus. They form inside the mouth only, unlike cold sores, which appear on the outside of the lips. The good news: you have several effective options to manage them at home, and a few signals that tell you when it’s time to get professional help.
What a Canker Sore Actually Is
Canker sores (aphthous ulcers) are shallow, painful open wounds that develop on the soft tissues inside your mouth, including the gums, inner cheeks, tongue, and the floor of your mouth. They typically look white or yellowish with a red border. Unlike cold sores, which are caused by herpes simplex virus and form on the outside of the mouth, canker sores are not viral and can’t spread from person to person.
No one knows exactly what triggers them, but several factors increase your chances of getting them. These include minor injuries to the gum tissue (from aggressive brushing, dental work, or biting your cheek), stress, hormonal changes, and certain food sensitivities. Nutritional gaps also play a role, which is worth exploring if you get canker sores frequently.
Home Remedies That Work
A saltwater rinse is one of the simplest and most effective first steps. Salt reduces acid levels in your mouth and helps calm inflammation, creating a better environment for healing. Mix 1 teaspoon of salt into 1 cup of warm water, swish for about 30 seconds, then spit. It will sting initially, but this method is well supported. Never put plain salt directly on the sore, as it will cause intense pain without improving healing.
Baking soda works through a similar mechanism. You can either add half a teaspoon to warm water as a rinse or make a paste with a few drops of water and dab it directly on the sore.
Honey, particularly manuka honey, has shown real benefits for canker sores. It reduces pain, inflammation, and ulcer size when applied directly to the sore several times a day. Honey contains natural compounds that kill bacteria and promote tissue repair. Just dab a small amount on the sore with a clean finger or cotton swab after meals and before bed.
Over-the-Counter Treatments
If home remedies aren’t cutting it, several OTC products can numb the pain and protect the sore while it heals. Look for products containing benzocaine, a topical numbing agent found in brands like Anbesol and Zilactin-B. These come as gels, pastes, or liquids that you apply directly to the sore. The key is to start using them as soon as you notice the ulcer forming, since early treatment tends to work best.
Antiseptic rinses containing hydrogen peroxide (like Orajel Antiseptic Mouth Sore Rinse) help keep the area clean and reduce bacteria that can slow healing. There are also protective pastes that form a barrier over the sore, shielding it from food and friction so it hurts less throughout the day.
For sores on the gums specifically, a gel or paste tends to stay in place better than a liquid rinse. Apply with a clean finger or cotton swab, and try not to eat or drink for at least 15 minutes afterward so the product has time to adhere.
Nutritional Deficiencies That Cause Recurring Sores
If you get canker sores repeatedly, a nutritional gap could be the underlying cause. Several specific deficiencies are linked to recurrent mouth ulcers:
- Vitamin B12: Supports red blood cell production and tissue repair. Low levels lead to poor healing of mouth tissues and can trigger recurring sores.
- Folic acid (vitamin B9): Essential for cell growth and repair. A deficiency causes oral inflammation and cracked lips alongside ulcers.
- Iron: Low iron reduces oxygen delivery to tissues, causing tongue soreness and mouth ulcers. This is especially common in people with anemia.
- Zinc: Supports immune function and tissue repair. Without enough zinc, ulcers take longer to heal and come back more often.
- Vitamin C: Strengthens blood vessels and promotes collagen formation. Deficiency weakens gum tissue and slows wound healing.
If you’re getting canker sores more than a few times a year, it’s worth asking your doctor to check these levels with a simple blood test. Correcting a deficiency often reduces or eliminates the problem entirely.
Switch Your Toothpaste
Sodium lauryl sulfate, the foaming agent in most toothpastes, has been associated with canker sores in multiple studies. In a 2012 clinical trial, 90 participants used two different toothpastes for eight weeks each. When they used the SLS-free version, their canker sores didn’t last as long and caused less pain compared to periods when they used SLS-containing toothpaste. Other research has found that switching to SLS-free toothpaste reduces the overall frequency of outbreaks.
SLS-free toothpastes are widely available. Brands like Sensodyne, Biotene, and several others skip this ingredient. If you get canker sores on your gums regularly, this is one of the easiest changes you can make.
Prescription Options for Severe Cases
When canker sores are large, extremely painful, or keep coming back, a dentist or doctor can prescribe stronger treatments. Prescription-strength steroid gels or pastes reduce inflammation more aggressively than anything available over the counter. These are applied directly to the sore and can shorten healing time noticeably for stubborn ulcers.
In some cases, a dentist may use chemical or laser cautery to seal the sore, which provides almost immediate pain relief and accelerates healing. This is typically reserved for sores that are unusually large or aren’t responding to other treatments.
What to Watch For
Most canker sores resolve within two weeks without any intervention. But a sore that lasts longer than two weeks, grows larger than a centimeter (roughly the size of a pea), or comes with a high fever warrants a call to your dentist or doctor. Unusually large or persistent ulcers can occasionally signal an underlying condition that needs attention.
Multiple sores appearing at once, or new sores forming before old ones heal, is another pattern worth getting checked. This kind of recurrence often points to one of the nutritional deficiencies mentioned above or, less commonly, an immune-related condition that a healthcare provider can help identify and manage.