Most mouth sores heal on their own within one to two weeks, but the right combination of treatments can cut pain dramatically and support faster healing. The key is identifying what type of sore you’re dealing with, then targeting it with the most effective approach available.
Identify Your Sore First
The two most common mouth sores look and behave very differently, and treating one like the other wastes time.
Canker sores appear inside the mouth, typically as a single round white or yellow sore with a red border. Their exact cause is unknown, but they’re often triggered by injury (biting your cheek, irritation from braces), stress, smoking, or deficiencies in folic acid, iron, or vitamin B12. They are not contagious.
Cold sores (fever blisters) show up on the outside of the mouth, around the lips, as a cluster of small fluid-filled blisters. They’re caused by herpes simplex virus type 1 (HSV-1) and are contagious. Cold sores require antiviral treatment to heal faster, so the home remedies below won’t do much for them. If you have blisters on or around your lips, an antiviral cream or prescription antiviral medication started within the first 48 hours is your best option.
The rest of this article focuses on canker sores and general mouth ulcers, since those are what most people are dealing with when they search for relief.
Salt Water Rinse: Your First Line of Defense
A warm salt water rinse is the simplest, cheapest thing you can do right now. Salt water creates a temporarily alkaline environment that discourages bacteria and promotes healing in soft tissue. Lab research on gum tissue cells found that rinsing with saline solution supported wound healing when used for two minutes, three times a day.
The effective ratio is about one teaspoon (5 grams) of table salt dissolved in one cup (250 ml) of warm water. Swish gently around the sore for about two minutes, then spit. Repeat three times daily, especially after meals. It will sting briefly on contact, but this fades within seconds. You can start this immediately and continue until the sore is gone.
OTC Numbing Gels for Quick Pain Relief
Over-the-counter oral gels containing benzocaine (typically at 20% concentration) numb the sore on contact. You apply a small amount directly to the ulcer, and the numbing effect kicks in within about two minutes. These products are widely available under brand names like Orajel and Anbesol.
The relief is temporary, usually lasting 15 to 30 minutes, but it can make eating and drinking bearable. Apply as needed throughout the day, following the product’s directions. Benzocaine products should not be used on children under two years old due to a rare but serious side effect that affects oxygen levels in the blood.
Some OTC products combine a numbing agent with a protective coating that sticks to the sore and shields it from further irritation. These adhesive patches or gel films can be especially helpful if the sore is in a spot that rubs against your teeth or gums constantly.
Prescription Options That Work Faster
If you need something stronger, a dentist or doctor can prescribe a corticosteroid paste. These anti-inflammatory treatments reduce swelling and pain more aggressively than anything over the counter. The typical approach is applying the paste directly to the sore twice a day, then avoiding food and drink for 15 minutes afterward and rinsing with water.
For people who get canker sores frequently, another clinical option is silver nitrate cauterization. A dentist applies it once directly to the ulcer. In a randomized controlled trial, 70% of patients treated with silver nitrate had significant pain reduction within one day, compared to just 11% in the placebo group. The catch: it doesn’t actually speed up healing time. Both treated and untreated sores healed at roughly the same rate, with about 83 to 89% fully healed by day seven. But if your main goal is to stop the pain fast while the sore heals naturally, a single application can provide relief that lasts for the duration of the ulcer.
What to Avoid While You Heal
Some everyday habits make mouth sores dramatically worse. Acidic foods and drinks like citrus, tomatoes, coffee, and soda irritate the exposed tissue and can extend healing time. Spicy foods do the same. Crunchy or sharp-edged foods like chips and crackers can physically reinjure the sore.
Alcohol-based mouthwashes are another common culprit. They burn on contact and can dry out the tissue around the ulcer. Switch to an alcohol-free mouthwash or stick with the salt water rinse until you’ve healed. If you use a toothpaste containing sodium lauryl sulfate (SLS), a common foaming agent, consider switching to an SLS-free brand. Some people find that SLS triggers or worsens canker sores.
Preventing Repeat Outbreaks
If you get canker sores regularly, the problem may be nutritional. Deficiencies in iron, folic acid, and vitamin B12 are all linked to recurrent mouth ulcers. A review of multiple studies found that a daily sublingual dose of 1,000 micrograms of vitamin B12, taken consistently for six months, significantly reduced the number of outbreaks, the number of ulcers per episode, and how long each ulcer lasted. The benefits became most noticeable after about six months of daily use.
This doesn’t mean B12 will help everyone. But if your sores keep coming back and you eat a diet low in animal products, or if you have digestive conditions that affect nutrient absorption, a B12 supplement is a low-risk option worth trying. Your doctor can also check your iron and folate levels with a simple blood test to rule out deficiency as a trigger.
Stress management matters too. Stress is one of the most commonly reported triggers for canker sores, and people who get recurrent outbreaks often notice a pattern tied to high-pressure periods at work, poor sleep, or illness.
When a Mouth Sore Needs Medical Attention
Most canker sores resolve within two weeks without any treatment at all. But a sore that persists beyond two weeks is no longer behaving like a typical ulcer. Any oral lesion present for more than two weeks warrants consideration for a biopsy, because self-limiting conditions like canker sores almost always resolve within that window. A sore that doesn’t heal could signal something more serious, including oral cancer, especially if it’s painless, irregularly shaped, or accompanied by a lump in your neck.
Other signs that warrant a visit: sores that are unusually large (bigger than a centimeter across), sores that keep coming back in clusters before the previous batch has healed, sores accompanied by high fever, or sores so painful that you can’t drink enough fluids to stay hydrated.