Most mouth sores heal on their own within one to two weeks, but you can speed the process and cut the pain significantly with a few straightforward steps. The right approach depends on what kind of sore you’re dealing with, so identifying it comes first.
Identify Your Mouth Sore
The two most common types are canker sores and cold sores, and they require different treatment.
Canker sores (aphthous ulcers) form inside the mouth, on the inner cheeks, lips, or tongue. They appear as a single round white or yellow sore with a red border. They are not contagious. Their exact cause is unknown, but common triggers include mouth injuries (biting your cheek, aggressive brushing), stress, smoking, and deficiencies in iron, folic acid, or vitamin B12.
Cold sores (fever blisters) form outside the mouth, typically around the border of the lips. They look like a cluster of small, fluid-filled blisters rather than a single open wound. Cold sores are caused by herpes simplex virus type 1, which an estimated 90 percent of U.S. adults carry. The virus stays dormant in nerve cells and periodically reactivates, sending blisters to the skin surface. Cold sores are contagious.
Location is the simplest way to tell them apart: inside the mouth means canker sore, outside the mouth means cold sore.
Saltwater Rinse: The Best Starting Point
A warm saltwater rinse is the single most useful thing you can do at home for a canker sore. Salt draws excess fluid out of inflamed tissue, shifts the mouth toward an alkaline environment where bacteria struggle to survive, and promotes the cell migration involved in wound repair. It works through osmosis, essentially pulling water out of bacteria and killing them.
Mix 1 teaspoon of salt into 8 ounces of warm water. Swish gently for 30 seconds, then spit. Repeat two to three times a day, especially after meals. If your sore is very tender and the rinse stings, drop to half a teaspoon of salt for the first day or two, then increase.
Other Home Remedies That Help
Beyond saltwater, a few additional strategies can reduce pain and shorten healing time:
- Ice or cold foods. Holding a small ice chip against the sore numbs the area and reduces inflammation. Popsicles and cold yogurt serve the same purpose.
- Honey. A dab of raw honey applied directly to a canker sore creates a protective coating and has natural antibacterial properties. Reapply after eating or drinking.
- Baking soda paste. Mix a small amount of baking soda with a few drops of water to form a paste, apply it to the sore, and let it sit for a few minutes before rinsing. Like saltwater, it neutralizes acids and discourages bacterial growth.
- Avoid irritating foods. Acidic foods (citrus, tomatoes), spicy dishes, and crunchy or sharp-edged snacks (chips, crackers) all aggravate open sores and slow healing. Stick to soft, bland foods until the sore closes.
Over-the-Counter Pain Relief
If a canker sore is painful enough to interfere with eating or talking, topical numbing products containing benzocaine can help. These come as gels, sprays, ointments, and lozenges. Gels and ointments can be applied directly to the sore up to four times a day. Lozenges dissolve slowly in the mouth and can be used every two hours as needed. The numbing effect is temporary, but it makes meals and conversation far more comfortable.
Protective pastes that form a barrier over the sore are another option. They shield the raw tissue from food, drink, and your teeth, which reduces pain and gives the area a chance to heal undisturbed. Look for products marketed specifically as oral wound protectants.
For cold sores, antiviral creams are available over the counter. These work best when applied at the very first sign of tingling, before the blister fully forms.
When Prescription Treatment Makes Sense
Canker sores that are large, unusually painful, or keep coming back sometimes need prescription-strength treatment. The most common option is a steroid mouth rinse. You swish the liquid in your mouth for about a minute after meals and before bed, then spit it out. The key detail: don’t eat or drink for at least 30 minutes afterward, because the medication works through direct contact with the tissue.
Steroid rinses are effective at calming the immune overreaction that drives severe canker sores, but they come with trade-offs. They suppress local immune defenses, which means oral yeast infections are a common side effect. They’re not appropriate if the sore is caused by an infection rather than an immune flare.
For cold sores that recur frequently or are severe, prescription antiviral pills can shorten outbreaks and reduce how often they happen.
Nutrient Deficiencies and Recurring Sores
If you get canker sores repeatedly, a vitamin deficiency could be a contributing factor. Research has linked recurrent canker sores to low levels of vitamin B12, folic acid, iron, and other B vitamins. In one study of 160 people with recurring sores, about 9 percent had low vitamin B12 levels at baseline. Correcting deficiencies through supplementation or dietary changes has been shown to reduce episodes or lead to remission in some people.
Good dietary sources of B12 include meat, fish, eggs, and dairy (or fortified plant milks). Folate is abundant in leafy greens, beans, and citrus. Iron comes from red meat, lentils, spinach, and fortified cereals. If you suspect a deficiency, a simple blood test can confirm it and guide whether supplements are worthwhile.
Prevent Sores From Coming Back
One of the most evidence-backed prevention strategies is switching to a toothpaste free of sodium lauryl sulfate (SLS), the foaming agent in most standard toothpastes. A systematic review published through the American Dental Association found that people who switched to SLS-free toothpaste had significantly fewer canker sores, shorter sore duration, fewer recurring episodes, and less pain. The reduction was meaningful: on average, about one fewer ulcer per observation period compared to SLS-containing toothpaste. Several SLS-free options are widely available in drugstores, often labeled as “gentle” or “sensitive” formulas.
Other prevention habits that help:
- Use a soft-bristled toothbrush. Hard bristles cause micro-injuries to gum and cheek tissue that can trigger sores.
- Manage stress. Stress is a well-documented trigger for both canker sores and cold sore outbreaks.
- Protect your lips from sun. UV exposure reactivates the herpes virus in many people. A lip balm with SPF helps prevent cold sore flare-ups.
- Fix sharp dental work. A chipped tooth, rough filling, or ill-fitting dental appliance that repeatedly scrapes your cheek or tongue can cause sores that won’t stop recurring until the irritant is addressed.
Sores That Don’t Heal in Two Weeks
Most canker sores resolve within 7 to 14 days without treatment. If a mouth sore persists beyond two weeks, doesn’t improve after removing obvious irritants, or interferes with your ability to eat and speak, it needs professional evaluation. A sore that lingers past the two-week mark is the standard threshold at which a biopsy is strongly recommended to rule out other conditions, including oral cancer. This is especially important for sores that are painless, have irregular borders, or appear in unusual locations like the floor of the mouth or the side of the tongue.