The most effective thing to put on a canker sore is an over-the-counter numbing gel containing benzocaine, applied directly to the sore as soon as it appears. Beyond numbing agents, you have several other options that protect the sore, reduce inflammation, or speed healing, and the best choice depends on how much pain you’re in and how long the sore has been there.
OTC Numbing Gels and Rinses
Products sold specifically for canker sores generally fall into three categories based on their active ingredient. Benzocaine gels (sold as Anbesol, Orabase, Zilactin-B, and others) numb the area on contact and are the most popular choice for immediate pain relief. You apply them directly to the sore with a clean finger or cotton swab, and they work within seconds.
Hydrogen peroxide rinses (like Orajel Antiseptic Mouth Sore Rinse) take a different approach. Instead of numbing, they clean the sore and reduce bacteria around it, which can help prevent the ulcer from getting worse. These are especially useful if you have multiple sores or sores in hard-to-reach spots where applying a gel is awkward.
A third option is a film-forming liquid that creates a physical barrier over the ulcer. Products like Soothe-N-Seal use a medical-grade adhesive that polymerizes into a thin, flexible film within about five seconds of application. This shield keeps food, drinks, and your tongue from irritating the raw tissue, which provides longer-lasting relief than a numbing gel alone. These patches are particularly helpful if eating has become painful.
Salt Water and Baking Soda Rinses
A simple homemade rinse is one of the most accessible treatments. Mix 1 teaspoon of table salt and 1 teaspoon of baking soda into 4 cups of warm water. Swish a mouthful gently over the sore for 30 seconds, then spit. The salt draws fluid from swollen tissue, and the baking soda creates a mildly alkaline environment that can soothe irritation. You can repeat this several times a day, especially after meals.
This rinse won’t numb the sore the way benzocaine does, but it keeps the area clean and creates conditions that support healing. Many people use it alongside a topical gel for the best results.
Honey
Honey has both antibacterial and anti-inflammatory properties, and research suggests it can reduce canker sore pain, size, and redness while helping prevent secondary infection. To use it, dab a small amount directly onto the sore about four times a day. Raw, unprocessed honey retains more of its beneficial compounds than standard grocery store honey, which is typically pasteurized at high heat and loses most of its nutrients in the process.
Prescription Options for Severe Sores
If over-the-counter products aren’t cutting it, a doctor or dentist can prescribe stronger treatments. The most common are topical steroid pastes containing hydrocortisone or triamcinolone, which reduce inflammation directly at the sore. These don’t just mask pain; they calm the immune response that’s keeping the ulcer inflamed. Studies show topical steroids reduce the number of days an ulcer lasts, though they don’t prevent future outbreaks.
For frequent or widespread sores, a prescription antiseptic rinse containing chlorhexidine can reduce the severity and pain of ulcers, even if it doesn’t stop new ones from forming. In rare, severe cases, systemic medications may be considered, but these carry more significant side effects and are reserved for people with chronic, debilitating outbreaks.
Foods to Avoid While Healing
What you keep away from the sore matters almost as much as what you put on it. Acidic foods (citrus, tomatoes, vinegar-based dressings), spicy dishes, salty snacks, and rough-textured foods like chips or crusty bread all irritate the exposed tissue and can extend healing time. Caffeine, eggs, cheese, peanuts, and almonds have also been identified as common triggers that may provoke new sores or worsen existing ones.
Stick to soft, bland, cool foods while the sore is at its worst. Yogurt, smoothies, oatmeal, and mashed potatoes are gentle enough to eat without wincing. Drinking through a straw can also help liquids bypass a sore on your lip or the front of your mouth.
Make Sure It’s Actually a Canker Sore
Before you start treating, confirm you’re dealing with the right thing. Canker sores appear inside the mouth as single, round white or yellow sores with a red border. They are not contagious. Cold sores (fever blisters), by contrast, show up on the outside of the mouth around the lips as clusters of small fluid-filled blisters and are highly contagious. Treatments for the two are completely different, so this distinction matters.
Most canker sores heal on their own within one to two weeks. But certain patterns warrant a call to your doctor or dentist: sores that are unusually large, sores lasting longer than two weeks, new sores developing before old ones heal, sores that extend onto the outer lip border, pain you can’t manage with OTC products, difficulty eating or drinking, or a high fever accompanying the sores.