Most canker sores heal on their own within two weeks, but the right home treatments can cut down on pain and help them resolve faster. These small white or yellow ulcers form inside the mouth, on the inner cheeks, lips, or tongue, and they can make eating and talking miserable while they last. Here’s what actually works to manage them at home.
Make Sure It’s a Canker Sore
Before treating anything, confirm you’re dealing with the right problem. Canker sores only form inside the mouth. Cold sores (fever blisters) are fluid-filled blisters that appear outside the mouth, usually around the border of the lips. If your sore is on the outer lip or skin around your mouth, it’s likely a cold sore, which is caused by a virus and requires a completely different approach.
A typical canker sore looks like a small, round white or yellow patch surrounded by red, inflamed tissue. It hurts, especially when food or your tongue touches it. Most are under a centimeter across.
Saltwater and Baking Soda Rinses
A simple rinse is the most accessible first-line treatment. Dissolve about half a teaspoon of salt in a cup of warm water and swish it around your mouth for 15 to 30 seconds before spitting it out. Repeat three or four times a day, especially after meals. Salt draws fluid from the inflamed tissue, which temporarily reduces swelling and pain.
Baking soda works similarly. Mix about a teaspoon of baking soda into a cup of warm water and use it as a rinse. Baking soda helps neutralize acids in the mouth that irritate the open sore, creating a less hostile environment for healing. You can alternate between salt and baking soda rinses throughout the day or combine them in one solution.
Hydrogen Peroxide Rinse
Diluted hydrogen peroxide acts as a mild antiseptic that helps keep the sore clean and reduces bacteria around the ulcer. Start with the standard 3% hydrogen peroxide sold in brown bottles at most drugstores, then mix one part peroxide with one part water to bring it down to roughly 1.5%. Swish gently for about 30 seconds and spit. You can also dab the diluted solution directly onto the sore with a cotton swab. Don’t swallow it, and don’t use it at full strength, as that can irritate the surrounding tissue.
Over-the-Counter Topical Products
Numbing gels and protective pastes sold at pharmacies can make a real difference, especially if the sore is in a spot that gets bumped constantly by your teeth or food. Products containing benzocaine (sold under names like Anbesol, Orabase, and Zilactin-B) temporarily numb the area on contact, giving you a window to eat or drink with less pain. Apply them directly to the sore with a clean finger or cotton swab.
Protective pastes create a physical barrier over the ulcer, shielding it from friction and acidic foods. These work best when applied after drying the sore gently with a tissue. The key with any topical product is timing: applying it as soon as the sore appears tends to produce better results than waiting a few days.
Honey
Applying honey directly to a canker sore is a home remedy with some clinical backing. In one study comparing honey to saline rinses for oral ulcers, the honey group reported symptom relief earlier than the control group. A separate small trial found that applying honey three times daily performed comparably to a standard prescription gel for both ulcer size and pain, with no adverse effects reported. Plain, unprocessed honey applied with a clean finger three times a day is a reasonable option, particularly if you prefer to avoid pharmacy products. Just expect it to sting briefly on contact.
Milk of Magnesia
Dabbing a small amount of liquid antacid (milk of magnesia) directly onto the sore can help neutralize the acidic environment around the ulcer. Acids from food and bacteria aggravate the exposed tissue, which is a big part of why canker sores hurt so much during meals. A thin coating of milk of magnesia acts as both a neutralizer and a mild protective layer. Apply it with a cotton swab a few times a day, and try not to eat or drink for several minutes afterward so it has time to work.
What to Avoid While Healing
What you keep away from the sore matters almost as much as what you put on it. Acidic foods like tomatoes, citrus fruits, and vinegar-based dressings directly irritate the exposed tissue. Spicy foods, salty chips, and anything with rough or sharp edges (think toast, crackers, tortilla chips) can reopen or aggravate the wound. Switching to softer, blander foods for a few days speeds up healing more than most people expect.
Avoid toothpastes containing sodium lauryl sulfate (SLS) if you get canker sores frequently. This foaming agent, found in many mainstream toothpastes, can irritate the mucous lining of the mouth and trigger new sores in some people. SLS-free options are widely available at most drugstores.
Nutritional Gaps That Cause Recurring Sores
If canker sores keep coming back, the problem may not be in your mouth. Several nutritional deficiencies are linked to recurrent outbreaks:
- Vitamin B12: found naturally only in animal-based foods like beef, poultry, eggs, and dairy. Deficiency is common in vegetarians and vegans.
- Folate (folic acid): a B vitamin found in fruits, vegetables, and meat that plays a direct role in cell repair. People with frequent canker sores often have lower blood levels of folate.
- Iron: iron-deficiency anemia is associated with canker sores, along with fatigue and weakness.
- Zinc: found primarily in meat and seafood, zinc supports immune function and wound healing. Low zinc levels are tied to slow-healing and recurrent ulcers.
- Calcium: found in dairy and leafy greens, calcium deficiency has been shown to cause or worsen canker sores, though the exact mechanism isn’t fully understood.
If you notice a pattern of recurring sores, especially combined with fatigue or other symptoms, a simple blood test can check for these deficiencies. Correcting a shortfall often reduces or eliminates the cycle.
When Home Treatment Isn’t Enough
Most canker sores resolve within two weeks without any treatment at all. Home remedies mainly manage pain and may shorten that timeline by a few days. But if a sore lasts longer than two weeks, is unusually large, spreads, or comes with fever, those are signs that something else may be going on, and a healthcare provider can evaluate whether a prescription-strength treatment or further testing is needed.