Most canker sores heal on their own within 10 to 14 days, but the right care can cut down pain significantly and help them resolve faster. These small white or yellow ulcers form inside the mouth, on the inner cheeks, lips, tongue, or soft palate, and they can make eating and talking miserable while they last. Here’s what actually works to speed things along and keep the pain manageable.
Quick Pain Relief Options
The fastest way to numb a canker sore is with an over-the-counter oral gel containing benzocaine, a local anesthetic that temporarily blocks pain signals in the tissue it touches. You apply it directly to the sore, and relief kicks in within a minute or two. Products like Orajel and Anbesol are widely available at pharmacies. Reapply as needed throughout the day, especially before meals.
If you prefer to skip the pharmacy, a simple saltwater rinse can reduce irritation and help keep the sore clean. Dissolve about half a teaspoon of salt in a cup of warm water and swish gently for 30 seconds. This won’t numb the pain the way benzocaine does, but it draws fluid from swollen tissue and creates an environment that’s less hospitable to bacteria.
Home Remedies That Hold Up
Honey applied directly to a canker sore performs surprisingly well. In a randomized clinical trial comparing honey to a prescription steroid paste, both treatments reduced ulcer size by about 60% within the first few days and led to complete healing by the third visit. Pain scores dropped at nearly identical rates in both groups, roughly 48% in the early days before full resolution. Raw honey has natural anti-inflammatory and antimicrobial properties, so dabbing a small amount on the sore two or three times a day is a reasonable approach if you want to avoid medication.
Hydrogen peroxide is another option. Mix equal parts standard 3% hydrogen peroxide and water, then apply the solution directly to the sore with a cotton swab. This helps clean the ulcer surface and can reduce bacteria around it. Avoid swallowing the mixture, and limit use to a few times per day so you don’t irritate the surrounding tissue.
Placing a wet black tea bag against the sore for a few minutes can also provide some comfort. Tea contains tannins, compounds with mild astringent and anti-inflammatory effects.
What to Eat and Avoid
Acidic foods are the biggest culprits for making a canker sore flare. Citrus fruits like oranges, lemons, and grapefruits cause a sharp sting on contact with the open sore and can slow healing. Tomatoes and tomato-based sauces, vinegar-heavy dressings, and carbonated drinks are similarly irritating due to their acidity and fizz. Spicy foods, crunchy chips, and crusty bread can physically scrape the ulcer and reopen healing tissue.
Stick to soft, bland foods while the sore is active. Yogurt, scrambled eggs, oatmeal, mashed potatoes, smoothies, and lukewarm soups are all easy on the mouth. Drinking through a straw can help liquids bypass the sore entirely.
Prescription Treatments for Stubborn Sores
When over-the-counter options aren’t enough, a doctor or dentist can prescribe a steroid dental paste. These pastes reduce inflammation directly at the ulcer site. The typical routine is to apply a thin layer after meals and before bed, pressing it onto the sore so it forms a protective coating. Most people notice improvement within a few days.
For canker sores larger than about 1 centimeter, or sores that persist for weeks, prescription treatment becomes more important. These larger ulcers, sometimes called major aphthous ulcers, can take up to six weeks to heal and may leave scarring. They sometimes come with fever, difficulty swallowing, and general fatigue. A specialist in oral medicine is the best resource for sores that severe or for people who get frequent outbreaks.
Nutritional Gaps That Fuel Recurrence
Recurring canker sores are sometimes linked to nutritional deficiencies. The nutrients most commonly associated with outbreaks are iron, vitamin B12, folic acid, and zinc. If you get canker sores frequently, it’s worth looking at whether your diet reliably includes sources of these nutrients: leafy greens and legumes for folate, red meat or fortified cereals for B12 and iron, and nuts or seeds for zinc. A blood test can confirm whether a deficiency is contributing to the pattern, and supplementation often reduces how often sores return.
Toothpaste and Prevention
You may have heard that switching to a toothpaste free of sodium lauryl sulfate (SLS), a common foaming agent, can prevent canker sores. The evidence here is underwhelming. A 2019 review found insufficient data to confirm that SLS-free toothpastes reduce ulcer frequency, duration, or pain. A double-blind study reached the same conclusion, finding no significant change in ulcer patterns after switching. That said, some people do notice subjective improvement, and SLS-free toothpastes are easy to find, so it’s a low-risk experiment if you’re dealing with frequent outbreaks.
Beyond toothpaste, using a soft-bristled brush and being gentle around the gums reduces the chance of accidentally creating a small wound that triggers a sore. Stress management also matters. Canker sores are commonly triggered by stress, fatigue, and minor mouth injuries.
Canker Sore vs. Cold Sore
The easiest way to tell these apart is location. Canker sores only form inside the mouth. Cold sores, also called fever blisters, form on the outside, typically around the border of the lips. Cold sores are caused by the herpes simplex virus (usually HSV-1) and are contagious. Canker sores have no known single cause, aren’t viral, and can’t spread to other people. If your sore is outside the mouth, on the lip border, or appears as a cluster of fluid-filled blisters, you’re likely dealing with a cold sore and need a different treatment approach, typically an antiviral.
Signs a Sore Needs Professional Attention
A typical minor canker sore, under a centimeter wide, should be noticeably improving by day seven and fully healed within two weeks. If a sore hasn’t healed after three weeks, is unusually large, keeps coming back in clusters, or is accompanied by high fever or difficulty swallowing, it warrants a visit to a dentist or doctor. Persistent or unusually large ulcers occasionally need a biopsy to rule out other conditions.