Most mouth ulcers heal on their own within one to two weeks without any specific treatment. What you can do in the meantime is reduce pain, avoid irritating the sore further, and create conditions that let your mouth heal faster. If you’re dealing with recurring ulcers, there are also practical steps to prevent them from coming back.
What You’re Dealing With
The most common type of mouth ulcer is a canker sore, which appears inside the mouth on the cheeks, lips, or tongue. It typically looks like a single round white or yellow sore with a red border. These are not the same as cold sores, which are fluid-filled blisters caused by the herpes virus and appear on the outside of the mouth around the lips. Canker sores aren’t contagious and don’t have a single known cause, though they can be triggered by mouth injuries (biting your cheek, rough brushing), stress, smoking, or nutritional deficiencies.
Home Treatments That Speed Healing
A salt water rinse is one of the simplest and most effective things you can try. Salt water acts as a natural disinfectant and reduces swelling around the ulcer. Mix one teaspoon of salt into one cup of warm (not hot) water, swish it around your mouth for 30 seconds, and spit. You can repeat this several times a day.
Honey is another option worth trying. A randomized study comparing honey to a standard prescription steroid paste found that honey reduced ulcer size, pain, and burning sensation just as effectively. Patients using honey also reported no side effects, while some using the steroid paste experienced mild reactions. Apply a small amount of raw honey directly to the sore a few times a day. It works as a natural anti-inflammatory and creates a protective coating over the ulcer.
Beyond rinses and topical remedies, avoid foods that aggravate the sore. Acidic fruits, spicy dishes, salty snacks, and rough-textured foods like chips or toast can all irritate an open ulcer and slow healing. Stick to softer, blander foods until the sore closes.
Over-the-Counter Pain Relief
If the ulcer is painful enough to interfere with eating or talking, a numbing gel or ointment containing benzocaine can help. These are available as gels, sprays, and ointments at most pharmacies. Apply them directly to the sore up to four times a day. Benzocaine products are not recommended for children under two years old.
You can also find over-the-counter mouth rinses formulated specifically for oral sores, often containing hydrogen peroxide or other antiseptic ingredients. These help keep the area clean and may reduce the risk of secondary infection, which can delay healing.
When Ulcers Keep Coming Back
If you get mouth ulcers frequently, the cause may be nutritional. Low levels of vitamin B12, folate, and iron are strongly linked to recurrent canker sores. One study found that 75% of people with recurring mouth ulcers were deficient in B12 or folate. Patients with low folate levels specifically had more frequent and more severe ulcers compared to those with normal levels. A simple blood test from your doctor can check for these deficiencies, and supplementation often reduces how often ulcers appear.
Your toothpaste could also be a factor. Many common toothpaste brands contain sodium lauryl sulfate (SLS), a foaming agent that can irritate the lining of the mouth. A systematic review published in the Journal of Oral Pathology & Medicine found that switching to an SLS-free toothpaste reduced ulcer frequency, size, duration, and pain across all four measures studied. If you’re prone to canker sores, this is one of the easiest changes you can make. Several brands market SLS-free formulas, and they’re widely available.
Professional Treatments for Stubborn Ulcers
For ulcers that are especially large or painful, a dentist or doctor can offer treatments that aren’t available over the counter. One option is chemical cauterization with a silver nitrate stick, which is touched directly to the ulcer. It’s quick, inexpensive, and patients often leave pain-free immediately afterward. This approach works best for people who get ulcers infrequently rather than chronically.
For more severe or persistent cases, a doctor may prescribe a stronger topical steroid paste or a medicated mouth rinse. These are typically reserved for major ulcers (larger than a centimeter) or clusters of small ulcers that don’t respond to standard care.
Signs an Ulcer Needs Medical Attention
A typical canker sore should heal within two to three weeks at most. If yours hasn’t healed by then, it’s worth getting checked. Oral cancer in its earliest stages often looks like a mouth ulcer, but there are key differences. Cancerous lesions are usually painless, which is the opposite of a canker sore. They may also have a small lump or bump underneath that you can feel with your tongue or finger.
Other warning signs include a small spot that keeps growing larger, a white patch that turns red, or a sore that starts bleeding when it previously didn’t. None of these guarantee cancer, but they all warrant a professional exam. Early-stage oral cancers are highly treatable when caught quickly.