Most canker sores hurt for 7 to 10 days before healing on their own, but you don’t have to wait it out. A combination of topical numbing agents, simple rinses, and protective barriers can cut the pain significantly and may speed healing. Here’s what actually works, starting with the fastest options.
Numbing Gels and Topical Anesthetics
The quickest relief comes from over-the-counter oral gels containing benzocaine, the same local anesthetic dentists use. Products like Orajel and Anbesol numb the sore on contact and keep pain suppressed for one to several hours. You apply a small amount directly to the sore with a clean finger or cotton swab. Reapply as needed throughout the day, following the directions on the package.
These gels work best right before meals, since eating is usually when canker sores hurt the most. The numbing effect is temporary, so think of them as a tool for getting through painful moments rather than a long-term fix.
Salt Water and Baking Soda Rinses
A simple rinse is one of the most reliable home remedies, and major cancer centers recommend it for patients dealing with mouth sores of all kinds. Memorial Sloan Kettering’s standard recipe: mix 1 teaspoon of salt and 1 teaspoon of baking soda into 1 quart (4 cups) of water. You can also use just salt or just baking soda if that’s what you have on hand, at the same ratio of 1 teaspoon per quart.
Swish gently for 30 seconds, then spit. Repeat every 4 to 6 hours, or more often if the pain is bothering you. The salt draws fluid out of the inflamed tissue, reducing swelling. Baking soda neutralizes acids in the mouth that can irritate the open sore. The sting you feel for the first few seconds fades quickly, and the relief that follows lasts longer than you’d expect from something so simple.
Protective Patches and Oral Bandages
If your sore is in a spot that constantly rubs against your teeth, lips, or tongue, a canker sore patch can make a big difference. Products like DenTek Canker Cover use a small tablet that you press onto the sore. Within about 30 minutes, it forms a clear gel-like bandage that seals and protects the ulcer for hours before dissolving on its own. You shouldn’t try to peel or remove the patch early.
The patch creates a physical barrier between the raw nerve endings in the sore and everything in your mouth: food, drinks, your tongue, your teeth. For sores on the inner lip or cheek, this type of protection often does more for comfort than numbing agents alone.
Honey as a Healing Agent
Honey isn’t just a folk remedy. A randomized clinical trial comparing honey to a prescription-strength topical steroid found that honey performed better on every measure: it reduced ulcer size faster, shortened the number of days patients experienced pain, and decreased redness more effectively. No side effects were reported in any group.
To use it, dab a small amount of plain honey directly onto the sore a few times per day. It forms a natural coating that protects the ulcer while its anti-inflammatory properties go to work. Raw, unprocessed honey is your best bet. Avoid flavored or heavily processed varieties.
Avoid Irritating Your Sore Further
What you stop doing matters as much as what you start doing. Spicy, acidic, and crunchy foods are the worst offenders. Citrus fruits, tomato sauce, chips, and anything vinegar-based will aggravate the sore and slow healing. Stick to soft, bland, cool foods when the pain is at its peak.
Your toothpaste may also be making things worse. Most commercial toothpastes contain sodium lauryl sulfate (SLS), a foaming agent that strips away the protective mucus layer inside your mouth. A clinical study found that switching to an SLS-free toothpaste significantly reduced both the duration of canker sores and daily pain scores in people prone to outbreaks. SLS appears to damage the lining of the mouth in a way that makes sores more likely and harder to heal. Brands marketed as “gentle” or “sensitive” are more likely to be SLS-free, but check the ingredient list to be sure.
Options From Your Dentist
If you have a canker sore that’s unusually painful or keeps you from eating normally, your dentist can offer treatments that go beyond what’s available over the counter.
Silver nitrate cauterization is a quick in-office procedure where a medicated stick is touched to the sore. It chemically seals the ulcer surface. In a controlled trial, 70% of patients treated with silver nitrate had significant pain reduction within one day, compared to just 11% in the placebo group. The effect is rapid, lasts for the remaining life of the sore, and requires only a single application. It doesn’t speed up healing, but it effectively eliminates the pain while the sore heals on its own schedule.
Dental laser treatment is another option gaining popularity. The procedure takes just a few minutes, and many patients report profound pain relief within minutes of treatment. Dentists who offer it report that treated sores often heal in about a day, compared to the usual 10-day timeline. Not every dental office has a laser, so you may need to call around.
For severe or frequently recurring sores, a dentist or doctor can prescribe a steroid mouth rinse. These reduce the inflammation driving the pain and help the sore heal faster, but they’re typically reserved for cases where over-the-counter approaches aren’t enough.
Nutritional Gaps That Fuel Recurring Sores
If canker sores keep coming back, the problem may not be in your mouth. Research consistently links recurrent canker sores to low levels of vitamin B12 and folate. One study found that people with frequent outbreaks had significantly lower daily intake of both nutrients compared to the general population. These were the only two vitamins, out of all those tested, that showed a meaningful difference.
Iron deficiency has also been flagged in multiple studies as a common finding in people with recurrent sores. You don’t necessarily need supplements. Foods rich in B12 (meat, fish, eggs, dairy), folate (leafy greens, beans, fortified grains), and iron (red meat, lentils, spinach) can help close the gap. If your sores are frequent and persistent, a blood test can identify whether a specific deficiency is contributing.
Signs a Canker Sore Needs Medical Attention
Most canker sores resolve within two weeks without any treatment. But Northwestern Medicine recommends seeing a doctor or dentist if a sore lasts longer than two to three weeks, is unusually large, or keeps recurring. A sore that won’t heal can occasionally signal something other than a simple canker sore, and persistent outbreaks sometimes point to an underlying condition worth investigating.