Most mouth sores heal on their own within one to two weeks, but the right treatment can cut pain significantly and speed recovery. What works best depends on the type of sore you have, so the first step is figuring out what you’re dealing with.
Identify the Type of Sore
The two most common mouth sores are canker sores and cold sores (fever blisters), and they require different treatment approaches. The easiest way to tell them apart is location. Cold sores appear on the outside of the mouth, typically around the border of the lips. Canker sores form inside the mouth, on the gums, inner cheeks, tongue, or soft palate.
They also look different. Cold sores show up as clusters of small, fluid-filled blisters. Canker sores are usually a single round sore, white or yellow in the center with a red border. Cold sores are caused by herpes simplex virus and are contagious. Canker sores are not caused by a virus and can’t spread to other people.
Home Rinses That Actually Help
A saltwater or baking soda rinse is one of the simplest and most effective first-line treatments for any mouth sore. Memorial Sloan Kettering Cancer Center recommends mixing 1 teaspoon of salt and 1 teaspoon of baking soda into 1 quart (4 cups) of water. You can also use just salt or just baking soda if you prefer. Swish the mixture in your mouth for 15 to 30 seconds, then spit it out. Repeat every 4 to 6 hours, or more often if needed. Use lukewarm water, not hot or cold.
This rinse works by creating a mildly alkaline environment that reduces bacteria around the sore and draws out some of the fluid causing swelling. It won’t taste great, but it’s free, safe for daily use, and genuinely reduces discomfort.
Over-the-Counter Pain Relief
For more immediate pain control, topical gels and pastes containing benzocaine (typically at a 20% concentration) numb the area on contact. Products like Orajel are widely available and provide temporary relief for canker sores, cold sores, and minor mouth injuries. Apply a small amount directly to the sore before meals to make eating less painful.
One thing to know: benzocaine can, in rare cases, cause a condition where the blood carries less oxygen than normal. If you have a history of allergies to local anesthetics (anything ending in “-caine”), avoid these products. For most people, occasional short-term use is fine, but don’t rely on it for weeks at a time.
Protective pastes that form a barrier over the sore are another option. These coat exposed nerve endings and shield the sore from food, drinks, and friction. They don’t numb the area but can make the sore less sensitive throughout the day.
Prescription Treatments for Stubborn Sores
If you get large or frequently recurring canker sores, a prescription-strength topical steroid can reduce inflammation and pain more aggressively than anything over the counter. These come in gels, pastes, or rinses and work by calming the immune response at the site of the sore. Your doctor or dentist can determine the right strength based on how severe and frequent your outbreaks are.
Prescription antimicrobial mouth rinses are another tool. They don’t prevent sores from coming back, but they reduce the severity and pain of active ulcers. For cold sores specifically, antiviral medications can shorten the duration of an outbreak, especially if started within the first day or two of symptoms.
In severe chronic cases that don’t respond to topical treatment, systemic medications taken by mouth exist, but they carry more significant side effects and are reserved for situations where sores are seriously affecting quality of life.
Foods to Avoid During an Outbreak
What you eat while you have an active sore matters more than most people realize. Acidic foods like oranges, lemons, pineapples, and strawberries irritate open sores and can delay healing. The same goes for tomato-based sauces, coffee, and alcohol, all of which are highly acidic.
Spicy foods, including hot sauces, curries, and jalapenos, disrupt the mouth’s lining and often have high salt content on top of their acidity. Hard, crunchy foods like chips, pretzels, toast, and raw vegetables can physically scrape or poke the sore, making it worse. Stick to soft, bland, room-temperature foods until the sore closes. Think oatmeal, scrambled eggs, smoothies, and mashed potatoes.
Some people also find that certain nuts (especially salted varieties), chocolate, and dairy trigger new canker sores or worsen existing ones. If you notice a pattern with specific foods, that’s worth paying attention to.
Preventing Sores From Coming Back
If you deal with recurrent canker sores, check your toothpaste ingredients. Sodium lauryl sulfate (SLS), the foaming agent in most toothpastes, is a known irritant that increases mouth sore frequency and pain in people who are prone to them. Switching to an SLS-free toothpaste is one of the easiest changes you can make, and several major brands now offer versions without it.
Nutritional deficiencies are another common underlying cause. Recurring mouth ulcers are frequently linked to low levels of vitamin B12, folate, or iron. These nutrients support cell repair and tissue regeneration in the mouth’s lining. When they’re low, that lining becomes more sensitive to irritation and breaks down more easily. If you get canker sores regularly and can’t identify a clear trigger, ask your doctor to check these levels with a simple blood test. Correcting a deficiency often reduces or eliminates outbreaks entirely.
Other common triggers include stress, lack of sleep, minor injuries from braces or sharp foods, and hormonal changes. Keeping a log of when sores appear can help you identify your personal pattern.
Signs a Mouth Sore Needs Medical Attention
Most mouth sores are harmless and resolve without intervention. But certain signs warrant a visit to your doctor or dentist. According to the Cleveland Clinic, you should seek evaluation if a canker sore lasts longer than two weeks or is larger than a centimeter (roughly the size of a pea).
A sore that won’t heal is also one of the primary signs of oral cancer. The Mayo Clinic notes that a lip or mouth sore that persists beyond two weeks, a white or reddish patch on the inside of the mouth, or an unexplained growth or lump should be examined. This doesn’t mean every lingering sore is cancer, but two weeks is the threshold where professional evaluation makes sense. Oral cancers caught early have much better outcomes, so it’s not something to put off.