Most canker sores heal on their own within 10 to 14 days, but you can speed up relief and reduce pain starting today with a combination of rinses, topical treatments, and smart food choices. The key is reducing irritation so the ulcer can close faster while managing pain in the meantime.
Salt Water and Baking Soda Rinses
The simplest and cheapest first step is rinsing your mouth with warm salt water or a baking soda solution. Dissolve 1 teaspoon of baking soda in half a cup of warm water and swish it around the sore for 15 to 30 seconds. You can do this several times a day, especially after meals. Salt water works similarly: about half a teaspoon of table salt in a cup of warm water. These rinses help keep the area clean, reduce bacteria, and create an environment that lets the tissue heal. It will sting for a moment, but the relief afterward is noticeable.
Over-the-Counter Numbing Gels
Topical numbing products containing benzocaine are the most widely available OTC option for canker sore pain. Benzocaine is a local anesthetic that temporarily blocks nerve signals at the surface of the sore. You apply it directly to the ulcer as a gel, ointment, or liquid up to four times a day, and it shouldn’t be used for more than two consecutive days without checking with a doctor. For children under two, benzocaine is not recommended due to toxicity concerns.
Other OTC options include protective pastes that form a barrier over the sore, shielding it from food and saliva. These don’t numb the pain as aggressively but can reduce irritation throughout the day and help the sore heal without repeated trauma from eating and talking.
Honey as a Topical Treatment
Applying honey directly to a canker sore is more than a folk remedy. Honey has antibacterial and antioxidant properties that promote wound healing, and clinical research supports its use on oral ulcers. In a randomized controlled trial studying oral mucositis (a condition that produces ulcers similar to canker sores), patients treated with Manuka honey had significantly less pain and less severe sores compared to a control group. A systematic review of 49 studies, including 12 randomized controlled trials, concluded that topical honey is beneficial in preventing or limiting the progression of oral ulcers.
To try it, dab a small amount of raw honey (Manuka if available) onto the sore a few times per day. It’s safe, inexpensive, and well tolerated, with no gastrointestinal side effects reported in clinical use.
Foods That Make Canker Sores Worse
What you eat while you have a canker sore matters enormously. Acidic and abrasive foods irritate the exposed tissue and can delay healing or intensify pain. The main culprits to avoid:
- Citrus fruits and juices: oranges, grapefruits, lemons, limes, pineapple
- Tomatoes and tomato-based sauces: pizza, marinara, tomato soup
- Coffee: contains salicylic acid, which irritates oral tissue
- Soda: high in acid regardless of whether it’s diet or regular
- Spicy foods: hot peppers and heavy spice blends
- Crunchy or sharp foods: chips, pretzels, nuts, and anything that could scrape the sore
Stick to soft, cool, bland foods while the sore is active. Yogurt, oatmeal, scrambled eggs, smoothies, and mashed potatoes are all safe choices that won’t aggravate the ulcer.
Switch to an SLS-Free Toothpaste
If you get canker sores repeatedly, your toothpaste may be part of the problem. Most toothpastes contain sodium lauryl sulfate (SLS), a foaming agent that is also a documented mucosal irritant. A systematic review published through the American Dental Association found that switching to an SLS-free toothpaste resulted in fewer ulcers, shorter ulcer duration, fewer recurring episodes, and less pain. In pooled data, people using SLS-free toothpaste developed roughly one fewer ulcer per cycle on average. Several brands sell SLS-free formulas, and they’re easy to find online or at most pharmacies.
Nutritional Deficiencies and Recurring Sores
Canker sores that keep coming back can signal a nutritional gap. Vitamin B12 deficiency has the strongest link: in one study, over 50% of patients with recurrent canker sores were deficient in B12, compared to none in the control group. When those deficient patients received B12 supplementation, 73% recovered completely. Low folate and low iron (ferritin) levels are also associated with recurrent ulcers, though the connection is less dramatic than with B12.
If you get canker sores more than a few times a year, it’s worth asking your doctor to check your B12, folate, and iron levels with a simple blood test. People following vegetarian or vegan diets, older adults, and those with absorption issues are especially prone to B12 deficiency. Celiac disease and gluten sensitivity can also trigger recurrent canker sores through both nutritional malabsorption and direct immune responses.
Prescription Options for Severe or Recurring Sores
Most canker sores don’t need a prescription, but major ulcers (larger than 1 centimeter across) can take up to six weeks to heal and may leave scars. For sores this severe, or for people who get frequent outbreaks, doctors can prescribe topical anti-inflammatory pastes that reduce swelling and pain at the ulcer site. These prescription-strength treatments calm the immune response in the tissue, which helps the sore close faster. They won’t prevent future outbreaks entirely, but they significantly cut down healing time and discomfort during active episodes.
Signs a Sore Needs Medical Attention
A typical canker sore is small, less than a millimeter across, and resolves within two weeks. You should see a doctor or dentist if a mouth sore bleeds, doesn’t heal after two weeks, or measures between 1 and 3 centimeters. Swelling in your neck lasting more than two weeks or a change in your voice (like hoarseness) that persists beyond two weeks also warrant a visit. These can be signs of a more serious condition, including oral cancer, which can initially look like a stubborn canker sore.