Most mouth ulcers (canker sores) can’t be “cured” instantly, but you can significantly speed healing and reduce pain with the right approach. Minor ulcers, the most common type, typically heal on their own within 10 to 14 days. The strategies below can shorten that timeline and keep ulcers from coming back.
What Actually Heals a Mouth Ulcer
Mouth ulcers heal from the bottom up as your body regenerates the damaged tissue. There’s no single treatment that makes one vanish overnight, but you can create the right conditions for faster healing and manage pain in the meantime. The two goals are protecting the ulcer from further irritation and reducing inflammation so your tissue can repair itself.
Salt Water Rinses
Rinsing with warm salt water is the simplest and most accessible first step. A study found that a roughly 7 percent concentration of table salt improved wound healing, and the National Dental Centre Singapore recommends gargling with warm salt water to neutralize the oral environment and promote healing. Mix about half a teaspoon of salt into a cup of warm water and swish gently for 30 seconds. Repeat a few times a day, especially after meals. Don’t rub salt directly on the ulcer, as this causes unnecessary pain without added benefit.
Over-the-Counter Pain Relief
Topical gels containing benzocaine (usually at 20 percent concentration) numb the ulcer on contact, making it easier to eat and drink. These can be applied up to four times a day. Some products also contain zinc chloride, an astringent that helps dry and protect the sore. Look for mouth-specific gels rather than general topical products, since they’re formulated to stick to wet tissue.
If the pain is more widespread or the ulcer is large, an anti-inflammatory painkiller taken by mouth can help reduce both swelling and discomfort.
Honey as a Treatment
Honey has real evidence behind it. A clinical trial comparing a honey-based spray to a standard prescription steroid ointment found no significant difference between the two in pain relief, healing time, or tissue recovery. Both groups saw meaningful pain reduction by day two, and average healing time was about five days in each group. If you want to skip the pharmacy, dabbing raw honey on the ulcer a few times a day is a reasonable alternative to medicated gels.
Nutritional Deficiencies That Cause Ulcers
If you get mouth ulcers repeatedly, the cause may be nutritional. Studies of patients with recurrent ulcers have found deficiencies in iron (about 20 percent of patients), vitamin B12 (around 5 percent), folic acid (about 3 percent), and general anemia (roughly 21 percent). These aren’t rare edge cases. If you’re getting ulcers every few weeks, it’s worth having your levels checked through a simple blood test.
Vitamin B12 deficiency in particular has a well-documented link. Researchers have described cases where recurrent ulcers resolved completely once B12 levels were corrected. Foods rich in B12 include meat, fish, eggs, and dairy. Iron-rich foods include red meat, lentils, and spinach. Folate is found in leafy greens, beans, and fortified grains.
Preventing Ulcers From Coming Back
Some people find that switching toothpaste helps. Sodium lauryl sulfate (SLS), the foaming agent in most toothpastes, has been suspected of irritating the oral lining and triggering ulcers. The evidence is mixed: one double-blind study found no significant change in ulcer patterns after switching to SLS-free toothpaste, while other research noted that removing probable allergenic substances from toothpaste reduced ulcer frequency. It’s a low-risk experiment. If you’re ulcer-prone, try an SLS-free toothpaste for a few months and see if the pattern changes.
Beyond toothpaste, common triggers include biting the inside of your cheek, sharp edges on teeth or braces, stress, lack of sleep, and acidic or spicy foods. Keeping a simple log of when ulcers appear can help you identify your personal triggers.
When an Ulcer Needs Professional Treatment
Major aphthous ulcers, those larger than 1 centimeter in diameter, can take up to six weeks to heal and sometimes leave scars. These often require prescription-strength treatment. A dentist or doctor may apply silver nitrate cautery, a chemical treatment that destroys the nerve endings in the ulcer. Clinical trials have shown this provides rapid, significant pain relief starting from the first day after the procedure and lasting through the following week.
Prescription steroid pastes or rinses are another option for severe or frequently recurring ulcers. These reduce the immune response that drives the inflammation.
When a Mouth Ulcer Could Be Something Else
A standard canker sore hurts, looks white or yellowish with a red border, and heals within two weeks. If an ulcer persists beyond two weeks, that’s a signal to get it examined. The Mayo Clinic lists a mouth sore that won’t heal as a potential sign of oral cancer, along with white or reddish patches, unexplained lumps, loose teeth, ear pain, or difficulty swallowing.
Recurrent ulcers can also be a symptom of systemic conditions. Behçet’s disease causes frequent, painful mouth ulcers that look like ordinary canker sores but tend to be more numerous. Celiac disease, Crohn’s disease, and other autoimmune conditions can present with chronic oral ulcers as well. If you’re getting clusters of ulcers regularly, or if they appear alongside other symptoms like joint pain, skin lesions, or digestive problems, those patterns are worth discussing with a doctor.