Most canker sores heal on their own within 4 to 14 days, but the right treatments can cut down pain and speed that timeline. These small, round ulcers with a white or yellow center and red border form inside the mouth, often along the inner lip, and while they’re not dangerous, they can make eating and talking miserable. Here’s what actually works to get rid of them faster and keep them from coming back.
Make Sure It’s Actually a Canker Sore
Before treating anything, it helps to confirm what you’re dealing with. Canker sores and cold sores are frequently confused, but they’re completely different conditions. Canker sores appear inside the mouth as a single round white or yellow sore with a red border. Cold sores (fever blisters) show up outside the mouth, typically around the border of the lips, as a cluster of small fluid-filled blisters. Cold sores are caused by the herpes virus and are contagious. Canker sores are not contagious and have no viral cause.
If your sore is on the outer lip and looks like a patch of tiny blisters, you’re likely dealing with a cold sore, which requires antiviral treatment rather than the approaches below.
Saltwater and Baking Soda Rinses
The simplest home treatment is a rinse. Dissolve 1 teaspoon of baking soda in half a cup of warm water and swish it around your mouth several times a day. A saltwater rinse (about half a teaspoon of salt in the same amount of warm water) works similarly. Both help reduce bacteria around the sore and create an environment that supports healing. These rinses sting briefly on contact but tend to reduce overall soreness within a day or two of consistent use.
Honey as a Topical Treatment
Plain honey applied directly to a canker sore is one of the more effective home remedies with real clinical support. In a study of 94 people with minor canker sores, those who applied honey four times a day for five days had significantly greater reductions in ulcer size, pain, and redness compared to groups using a topical corticosteroid paste or a protective oral base alone. No side effects were reported. Use a clean finger or cotton swab to dab a small amount of raw honey directly on the sore after meals and before bed.
Over-the-Counter Pain Relief
Pharmacy shelves carry several options for canker sore pain. Numbing gels and liquids containing benzocaine can temporarily dull the area so you can eat and drink without wincing. Protective pastes create a barrier over the sore, shielding it from food and saliva. These products won’t dramatically shorten healing time, but they make the days while you wait much more comfortable. Apply them to a dry sore for the best adhesion.
When Prescription Treatment Helps
Most canker sores don’t need a prescription. But major canker sores, those larger than 1 centimeter, can last anywhere from 10 days to 6 weeks and often cause significant pain. For these, a doctor or dentist can prescribe a steroid paste that you apply directly to the dried ulcer several times a day until it heals. For widespread sores affecting large areas of the mouth, a prescription steroid mouth rinse (swish and spit, twice daily) can reach spots a paste can’t. These treatments reduce inflammation and typically shorten healing time considerably.
Avoiding Triggers That Make Them Worse
While a sore is active, acidic foods like citrus, tomatoes, and vinegar-based dressings will intensify pain and can irritate the tissue further. Spicy foods and rough, crunchy items like chips and crackers do the same. Stick to soft, bland foods until the sore closes. Drinking through a straw can help liquids bypass the sore entirely.
Switching Your Toothpaste
If you get canker sores repeatedly, your toothpaste may be part of the problem. A systematic review of clinical trials found that toothpaste free of sodium lauryl sulfate (SLS), a common foaming agent, significantly reduced the number of ulcers, the duration of each ulcer, the number of episodes, and the level of pain compared to standard SLS-containing toothpaste. Several brands market SLS-free formulas specifically. This is one of the easiest changes you can make, and for people with recurrent sores, it often makes a noticeable difference within a few months.
Nutritional Deficiencies and Recurrence
People who get canker sores frequently tend to have lower intakes of certain nutrients, particularly vitamin B12 and folate. One study found that people with recurrent canker sores consumed about 7% less B12 and 20% less folate daily than the general population. Broader blood screenings have found nutritional deficiencies in roughly 14 to 18 percent of people with chronic canker sores, with B12, folate, and iron being the most common gaps. When those deficiencies are corrected through supplementation or dietary changes, symptoms often improve.
Good dietary sources of B12 include meat, fish, eggs, and dairy. Folate is abundant in leafy greens, beans, and fortified grains. If you get canker sores more than a few times a year, it’s worth having your levels checked with a simple blood test.
How Long Each Type Takes to Heal
Not all canker sores are the same, and knowing which type you have sets realistic expectations:
- Minor canker sores are the most common type, measuring 2 to 5 millimeters across. They heal on their own in 4 to 14 days without scarring.
- Major canker sores are 1 to 3 centimeters in diameter, noticeably deeper, and can take 10 days to 6 weeks to resolve. These sometimes leave scars and usually benefit from prescription treatment.
- Herpetiform canker sores appear as clusters of very small (1 to 2 millimeter) ulcers grouped together. Despite the name, they have nothing to do with the herpes virus. They typically clear within 7 to 10 days.
Signs a Sore Needs Professional Attention
Any mouth ulcer lasting more than 10 to 14 days without signs of healing should be evaluated by a dentist or doctor. The American Academy of Oral Medicine recommends a biopsy for persistent ulcers to rule out other conditions that can look similar to canker sores but require different treatment. Sores that are unusually large, spreading, accompanied by high fever, or making it difficult to drink fluids also warrant a professional visit sooner rather than later.