Most canker sore pain responds well to a combination of topical numbing agents and simple rinses you can start at home today. A typical canker sore heals on its own within 7 to 10 days, but the first few days can be miserable, especially when eating, drinking, or talking. Here’s what actually works to cut that pain short.
Numb the Sore Directly
The fastest relief comes from over-the-counter topical gels containing 20% benzocaine. Products like Orajel and Red Cross Canker Sore Medication use this local anesthetic to temporarily block pain signals from the nerve endings in your mouth. You apply a small amount directly to the sore, and the numbing effect kicks in within a minute or two. It won’t last all day, so you’ll need to reapply several times, particularly before meals.
Another OTC option is a protective paste that forms a barrier over the sore. These seal off the raw tissue from contact with food, drinks, and your teeth, which is often what triggers the sharpest pain. Some products combine a numbing agent with a protective coating, giving you both immediate relief and longer-lasting coverage.
Salt Water and Baking Soda Rinses
A salt water rinse is the simplest home remedy and genuinely effective. Mix one teaspoon of salt into a cup of warm water, swish it around the sore for 30 seconds, then spit it out. Repeat a few times a day. The salt draws fluid from the inflamed tissue, which reduces swelling and eases the throbbing feeling. It also creates an environment that’s less hospitable to bacteria, helping the sore heal cleanly.
Baking soda works similarly. Dissolve one teaspoon in a cup of warm water and use it the same way. Baking soda neutralizes acids in the mouth that can irritate the open sore, so it’s especially helpful after eating acidic foods like tomatoes or citrus.
Honey as a Healing Agent
Applying honey directly to a canker sore does more than just coat it. In a clinical trial comparing honey to a standard prescription steroid paste, participants using honey saw their ulcers shrink in an average of about 2.7 days, compared to nearly 6 days for the steroid group and 7 days for a plain paste. Honey also reduced pain and redness more effectively. You can dab a small amount of raw, unprocessed honey onto the sore several times a day, especially after meals. It stings briefly on contact but tends to soothe within seconds.
When OTC Options Aren’t Enough
If your canker sore is large, unusually painful, or keeps coming back, a dentist or doctor can offer stronger options. Prescription steroid pastes containing triamcinolone acetonide are commonly prescribed, though recent research suggests their healing advantage over placebo is modest. Their main benefit is reducing inflammation and discomfort during the worst days.
Some dental offices now use low-level laser therapy, where a small diode laser is directed at the sore for about 30 seconds per session. Most sores need only one or two sessions. Patients typically report that the sore becomes pain-free after treatment, with only mild sensitivity to touch remaining. The procedure itself is painless and requires no anesthesia.
Avoid What Makes It Worse
While you’re healing, certain foods and habits will keep the pain firing. Acidic foods (oranges, tomatoes, vinegar-based dressings), spicy dishes, and crunchy or sharp-edged foods like chips and crusty bread all irritate the exposed tissue. Stick to softer, cooler, or room-temperature foods until the sore closes up. Drinking through a straw can help liquids bypass the sore if it’s on your lip or the front of your mouth.
Your toothpaste may also be a factor. A systematic review of clinical trials found that toothpastes containing sodium lauryl sulfate (SLS), a common foaming agent, significantly increased the number of canker sores, how long they lasted, and how much they hurt. Switching to an SLS-free toothpaste reduced ulcer frequency, duration, and pain across all the studies reviewed. Brands like Sensodyne, Biotene, and some Arm & Hammer varieties are SLS-free. If you get canker sores regularly, this one change is worth trying first.
Prevent Recurring Sores
Some people get canker sores once in a while. Others deal with them constantly. If you’re in the second group, a nutritional gap may be driving the cycle. Vitamin B12 deficiency is one of the most well-documented triggers. A review of the clinical evidence found that taking 1,000 micrograms of sublingual B12 daily for six months significantly reduced the number, duration, and frequency of outbreaks. Sublingual tablets dissolve under the tongue and absorb directly into the bloodstream, which tends to work better than swallowing a pill for this purpose.
Iron, folate, and zinc deficiencies have also been linked to recurrent canker sores. If yours keep coming back despite avoiding obvious triggers, a blood test checking these levels can reveal whether supplementation might help.
Stress is another well-known trigger, and many people notice sores appearing during high-pressure periods at work or school. You can’t always eliminate stress, but recognizing the pattern helps you act quickly with rinses and topical treatment at the first sign of a sore forming.
Signs a Sore Needs Medical Attention
A standard canker sore is small, round or oval, with a white or yellowish center and a red border. It hurts but heals within two weeks. Any mouth sore that lasts longer than two weeks should be evaluated by a doctor or dentist. Cleveland Clinic specifically flags these warning signs that distinguish a potentially serious lesion from an ordinary canker sore: red, white, or mottled patches in the mouth; a bump or lump under the skin beneath the sore; bleeding that won’t stop; rough, crusty, or cracked texture changes; visible lumps or swelling in the neck, cheek, or jaw; and voice changes like hoarseness lasting more than two weeks. None of these are typical of a canker sore, and all warrant prompt evaluation.