Most mouth sores are canker sores, and they heal on their own within 10 to 14 days. But you can speed up relief and reduce pain with a few simple treatments at home. The right approach depends on what type of sore you’re dealing with and what’s triggering it.
First, Figure Out What You Have
The two most common types of mouth sores look and behave quite differently. Canker sores form only inside the mouth, on the inner cheeks, lips, or tongue. They’re typically a single round white or yellow sore with a red border. They are not caused by a virus, and they’re not contagious. Their exact cause isn’t fully understood, but they can be triggered by injury (like biting your cheek), stress, smoking, or nutritional deficiencies in iron, vitamin B12, or folate.
Cold sores (fever blisters) are clusters of small fluid-filled blisters that appear outside the mouth, usually around the border of the lips. These are caused by the herpes simplex virus, typically type 1. Cold sores require a different treatment approach, often involving antiviral medication, so this distinction matters.
If your sore is inside your mouth and isn’t a fluid-filled blister, you’re almost certainly dealing with a canker sore. The remedies below are focused on that.
Salt Water Rinse
The simplest and most effective home treatment is a salt water rinse. Mix 1 teaspoon of salt into 8 ounces of warm water until it’s fully dissolved. Swish it around your mouth for 15 to 30 seconds, then spit it out. You can do this up to four times a day. If it stings too much, cut the salt to half a teaspoon. Salt water helps clean the sore and draw out fluid, which can reduce swelling and promote faster healing.
Over-the-Counter Pain Relief
Numbing gels and ointments containing benzocaine can take the edge off, especially before eating. Apply a small amount directly to the sore as needed, but no more than four times a day. These products don’t speed healing, but they make the sore far more bearable. Look for them in any pharmacy, usually in the oral care aisle near toothache products.
Hydrogen peroxide rinses (diluted to a 1.5% or 3% solution mixed with equal parts water) can also help keep the area clean and prevent secondary infection. You can alternate between a salt water rinse and a peroxide rinse throughout the day.
Honey as a Topical Treatment
Applying raw honey directly to a canker sore is a well-studied home remedy. In clinical comparisons, honey performed just as well as standard prescription gels for reducing both pain and ulcer size when applied three times daily for five days. Participants reported noticeable improvement in pain and sore size with no adverse effects. If you want a natural option, a dab of honey on the sore a few times a day is a reasonable choice.
Check Your Toothpaste
If you get canker sores repeatedly, your toothpaste may be part of the problem. Many toothpastes contain sodium lauryl sulfate (SLS), a foaming agent that can irritate the lining of your mouth. Research on this is surprisingly clear: in one study, patients who switched from an SLS-containing toothpaste to an SLS-free version went from an average of 14.3 ulcers over three months down to 5.1. That’s a 64% reduction just by changing toothpaste.
A 2019 systematic review looking at four separate clinical trials with 124 participants confirmed this across the board. SLS-free toothpaste significantly reduced the number of ulcers, how long each one lasted, the number of flare-ups, and how much they hurt. Check your toothpaste’s ingredient list for sodium lauryl sulfate, and if it’s there, try switching to an SLS-free brand for a few months to see if your sores become less frequent.
Nutritional Gaps That Cause Recurring Sores
Mouth sores that keep coming back can signal a nutritional deficiency. Low levels of iron, vitamin B12, or folate are all linked to recurrent canker sores. Vitamin B12 or folate deficiency can also cause a sore, red tongue alongside mouth ulcers. If you’re getting sores frequently and can’t pin them on a trigger like stress or an injury, it’s worth having your levels checked with a simple blood test. Correcting a deficiency often reduces or eliminates recurrent sores entirely.
Foods rich in B12 include meat, fish, eggs, and dairy. Folate is found in leafy greens, beans, and fortified grains. Iron comes from red meat, lentils, spinach, and fortified cereals. If your diet is limited or you follow a plant-based diet, a supplement may help.
Other Common Triggers to Avoid
While your sore is healing, acidic foods like citrus fruits, tomatoes, and vinegar-based dressings will sting and can slow recovery. Spicy foods and rough, crunchy foods like chips or toast can physically irritate the sore and make it worse. Stick to softer, blander foods until the sore closes up.
For prevention, pay attention to patterns. Canker sores are often triggered by accidental bites to the cheek or tongue, sharp edges on braces or dental work, periods of high stress, or hormonal changes. Keeping a simple log of when sores appear can help you identify your personal triggers over time.
When a Mouth Sore Needs Medical Attention
A sore that hasn’t healed after two weeks warrants a visit to your doctor or dentist. The Mayo Clinic specifically flags any lip or mouth sore that won’t heal as a potential sign of oral cancer, along with white or reddish patches inside the mouth, a lump or growth, unexplained mouth or ear pain, and difficulty swallowing. These symptoms don’t automatically mean cancer, but they need to be evaluated.
You should also seek care if your sores are unusually large, spreading, accompanied by a high fever, or so painful that you can’t eat or drink enough fluids. A doctor can prescribe stronger topical treatments or investigate underlying conditions that may be driving recurrent sores.