Most mouth ulcers (canker sores) heal on their own within 10 to 14 days, but you can speed that timeline and reduce pain significantly with the right approach. These small, round sores with a white or yellow center and red border affect roughly one in five people at some point, and while they’re not dangerous, they can make eating and talking miserable. Here’s what actually works to get rid of them faster.
Saltwater Rinses and Other Home Remedies
The simplest treatment is a saltwater rinse: dissolve 1 teaspoon of salt in 8 ounces of warm water, swish it around your mouth for 15 to 20 seconds, and spit. If the rinse stings too much, cut the salt to half a teaspoon for the first day or two. You can do this several times a day, especially after meals, to keep the ulcer clean and reduce bacteria around the wound.
Baking soda rinses work similarly. Mix 1 teaspoon of baking soda in a half cup of warm water and rinse the same way. Both options help neutralize acids in the mouth that irritate the open sore. Honey applied directly to the ulcer has mild antibacterial properties and can form a protective coating, though it will need reapplication after eating or drinking.
Over-the-Counter Treatments That Help
Topical gels and pastes containing pain-relieving ingredients like menthol or benzocaine can numb the area and make it easier to eat. You apply them directly to the ulcer, and they create a barrier that shields the sore from further irritation. Look for products specifically labeled for mouth ulcers or oral pain relief at any pharmacy.
Antiseptic mouthwashes containing chlorhexidine can help prevent secondary infection, which sometimes slows healing. Protective paste products that stick to the ulcer and form a physical barrier are especially useful if the sore is in a spot that rubs against your teeth or cheeks constantly.
Clinical Treatments for Stubborn Ulcers
If home remedies aren’t cutting it, a dentist or doctor can offer faster options. One of the most effective is silver nitrate cauterization, a quick in-office procedure where a chemical stick is applied directly to the ulcer. In a clinical trial of 65 patients, those treated with silver nitrate healed in an average of 2.7 days, compared to 5.5 days for the placebo group. By day seven, 60% of the treated group had fully healed versus 32% of controls. No side effects were recorded. A separate trial of 125 patients found silver nitrate eliminated symptoms in just over one day on average, compared to nearly five days for placebo.
For severe or frequently recurring ulcers, doctors may prescribe stronger topical treatments, including steroid gels or pastes that reduce inflammation and pain more aggressively than anything available over the counter.
What Triggers Mouth Ulcers
Understanding your triggers is the most effective long-term strategy. Common culprits include physical injury to the mouth (biting your cheek, sharp edges on braces or dentures, vigorous tooth brushing), stress, and certain foods. Chocolate, peanuts, and eggs are among the foods most frequently reported to worsen outbreaks. Acidic foods like citrus, tomatoes, and vinegar won’t necessarily cause new ulcers, but they will make an existing one hurt more.
Nutritional deficiencies play a role for some people. Deficiencies in vitamin B12, folate, and iron have been found in 18% to 28% of people with recurrent mouth ulcers, compared to about 8% in the general population. Correcting the deficiency improves symptoms in some of those cases, so if you get ulcers frequently, it may be worth asking for a blood test.
Switch Your Toothpaste
One surprisingly effective prevention strategy is switching to a toothpaste without sodium lauryl sulfate (SLS), the foaming agent in most mainstream toothpastes. SLS can strip away the delicate lining of the mouth, and research has shown it increases the frequency of recurrent ulcers. One clinical study found four times fewer soft tissue lesions after using an SLS-free toothpaste compared to one containing SLS. If you get mouth ulcers regularly, this is one of the easiest changes you can make. SLS-free options are widely available at most drugstores.
Canker Sores vs. Cold Sores
Before treating a mouth ulcer, make sure you’re dealing with the right thing. Canker sores appear inside the mouth as single, round sores with a white or yellow center. Cold sores (fever blisters) appear on the outside of the mouth, usually around the border of the lips, as clusters of small fluid-filled blisters. Cold sores are caused by a virus and are highly contagious. Canker sores are not contagious at all and have no viral cause. The treatments for each are completely different, so the distinction matters.
Know the Three Types
Not all mouth ulcers behave the same way. Minor ulcers are the most common type, typically small and self-limiting, healing within 10 to 14 days without treatment. Major ulcers are larger, deeper, and can take up to a month to heal, sometimes leaving scars. Herpetiform ulcers (despite the name, not caused by herpes) appear as clusters of tiny sores that can merge into larger irregular ulcers, lasting anywhere from 10 to 100 days and causing significant discomfort.
If you’re dealing with a minor ulcer, home treatment is usually all you need. Major or herpetiform ulcers often benefit from professional treatment.
When an Ulcer Needs Medical Attention
An ulcer that hasn’t healed after three weeks should be evaluated by a doctor or dentist. Guidelines in the UK, where mouth cancer screening is well-established, flag any unexplained mouth ulcer lasting three or more weeks as warranting an urgent specialist referral. This doesn’t mean a lingering ulcer is cancer, but persistent ulcers that don’t follow the normal healing pattern need a professional look to rule out something more serious. The same applies to ulcers that are unusually large, extremely painful, accompanied by a lump in the neck, or that keep coming back in the same spot.