Most canker sores heal on their own within a few weeks, but you can speed up the process and cut the pain significantly with the right combination of home care and over-the-counter products. The key is reducing irritation, managing pain, and giving the tissue what it needs to repair itself.
How Long Canker Sores Take to Heal
The timeline depends on the type of sore you’re dealing with. Minor canker sores, the most common kind, are smaller than a pea and typically clear up within two to three weeks without scarring. Herpetiform canker sores, which show up as clusters of tiny pinpoint ulcers, heal in about two weeks as well.
Major canker sores are a different story. These are larger than one centimeter, extremely painful, and can take months to fully heal. They often leave scars. If your sore is unusually large or has lasted more than two weeks, it’s worth getting it looked at by a doctor or dentist.
Salt Water Rinse: The Simplest First Step
A salt water rinse is the cheapest, most accessible way to start treating a canker sore at home. Dissolve 1 teaspoon of salt in 1 cup of water, swish it around your mouth for 30 to 60 seconds, and spit it out. The salt draws fluid from the swollen tissue, which helps reduce inflammation and creates a less hospitable environment for bacteria. Repeating this several times a day, especially after meals, keeps the area cleaner and can noticeably reduce discomfort.
Over-the-Counter Pain Relief
Topical products containing benzocaine are widely available and work by numbing the nerve endings directly at the sore. You can find benzocaine in gels, ointments, sprays, and swabs. Apply it to the affected area up to four times a day. Lozenges are another option, dissolved slowly in the mouth every two hours as needed. These won’t speed healing, but they make eating and talking far more tolerable while you wait for the sore to close up.
Protective pastes that coat the ulcer can also help. They create a barrier between the raw tissue and everything in your mouth, including food, drinks, and your teeth. Look for products marketed specifically for mouth sores, as they tend to adhere to wet surfaces better than general wound care products.
Foods That Make Canker Sores Worse
What you eat while you have a canker sore matters more than you might expect. Acidic foods irritate the exposed tissue, increase pain, and can slow healing. The biggest offenders include:
- Citrus fruits and juices: oranges, lemons, grapefruits, and limes
- Tomatoes and tomato-based products: sauce, ketchup, salsa
- Coffee and carbonated drinks: both acidic, and hot coffee adds thermal irritation
- Strawberries: contain natural acids that irritate sensitive mouth tissue
Spicy and crunchy foods also deserve caution. A sharp chip edge or a bite of something heavily seasoned can re-traumatize the sore and essentially reset the healing clock. Stick to softer, blander foods until the sore starts closing. Yogurt, oatmeal, scrambled eggs, and smoothies (made without citrus) are good options.
Honey as a Topical Treatment
Applying honey directly to a canker sore is a popular home remedy, and there’s some clinical evidence behind it. In a small trial comparing honey to salicylate gel (a standard prescription treatment for mouth ulcers), both groups saw similar improvements in ulcer size and pain over five days of application three times daily. No participants reported side effects from the honey. While the results weren’t statistically significant between the two groups, honey performed roughly as well as the medicated gel, which makes it a reasonable option if you want to avoid pharmacy products. Use raw, unprocessed honey and dab it directly on the sore after meals.
Nutritional Gaps That Cause Recurring Sores
If you get canker sores frequently, the problem may not be in your mouth at all. Deficiencies in certain vitamins directly compromise the lining of your mouth, making it more fragile and slower to repair.
Vitamin B12 is one of the most well-documented links. B12 supports DNA synthesis and helps maintain the mucosal tissue inside your mouth. When levels drop, the cells that line your cheeks and gums can’t turn over and repair themselves properly, leaving you vulnerable to ulcers. Good sources include meat, fish, eggs, and dairy. People who eat plant-based diets are at higher risk for deficiency.
Folate (vitamin B9) plays a similar role. It fuels the rapid cell turnover that keeps your oral lining intact. Low folate disrupts this process and weakens mucosal integrity. Leafy greens, legumes, and fortified grains are reliable dietary sources.
Vitamin C rounds out the trio. It’s essential for collagen synthesis and tissue repair. When you’re deficient, wounds heal more slowly and your mucosal tissue becomes more fragile. Ironically, the best food sources of vitamin C (citrus fruits, strawberries) are the same ones that irritate active sores. If you suspect a deficiency is contributing to recurring canker sores, a supplement lets you get the vitamin without the acid.
Professional Treatments for Stubborn Sores
For canker sores that won’t respond to home care, a dentist or doctor can offer stronger interventions. Chemical cauterization is one of the more effective in-office options. A topical solution called Debacterol chemically cauterizes the sore and can reduce healing time to about a week for serious ulcers. Silver nitrate is another cauterizing agent. It won’t necessarily speed healing, but it typically provides immediate pain relief by sealing the nerve endings at the surface of the ulcer.
For people with severe or frequently recurring sores, prescription steroid mouthwashes can tamp down the inflammatory response that keeps ulcers from healing. These come as soluble tablets that you dissolve in a few teaspoons of water, swish around your mouth for three to four minutes, and spit out. You use them once daily, ideally after eating or brushing, and avoid food or drink for at least 30 minutes afterward. Some people experience a burning or stinging sensation in the first few days, which usually fades. Oral thrush is an occasional side effect with extended use.
Preventing the Next One
Once you’ve dealt with a canker sore, prevention becomes the real goal. A few practical habits reduce flare-ups considerably. Use a soft-bristled toothbrush to avoid scraping the inside of your mouth. Choose toothpaste without sodium lauryl sulfate (SLS), a foaming agent that strips the protective mucous layer and is a well-known trigger for people prone to canker sores.
Pay attention to patterns. Many people notice sores appearing after eating specific foods, during periods of high stress, or around hormonal changes. Keeping a simple log of when sores appear and what preceded them can reveal your personal triggers. If you’re getting sores more than a few times a year, ask your doctor to check your B12, folate, and vitamin C levels. Correcting a deficiency can dramatically reduce how often sores come back.