Most mouth ulcers are minor canker sores, smaller than 5 mm across, that heal on their own within two weeks. But you don’t have to wait it out in pain. A combination of home rinses, over-the-counter products, and smart prevention habits can reduce discomfort, speed healing, and keep ulcers from coming back.
What Type of Mouth Ulcer You’re Dealing With
Not all mouth ulcers behave the same way, and knowing the difference helps you choose the right approach. Minor aphthous ulcers are the most common type. They’re small, round, shallow sores that show up on the inner cheeks, lips, tongue, or soft palate. They hurt for a few days, then gradually heal within about two weeks without leaving a scar.
Major aphthous ulcers are larger than 10 mm, dig deeper into the tissue, and can last 5 to 10 weeks. These often leave scarring and typically need medical treatment rather than just home care. A third type, called herpetiform ulcers, appears as clusters of tiny sores (2 to 3 mm each) that can merge into one large, irregular ulcer. Despite the name, they aren’t caused by the herpes virus. They usually heal within one to two weeks, though the merged ones may scar.
If your ulcer is small, appeared after biting your cheek or eating something acidic, and is already starting to improve after a few days, you’re almost certainly dealing with a minor canker sore and can treat it at home.
Salt Water Rinse: The Simplest First Step
A warm salt water rinse is the most accessible treatment you can start immediately. It draws fluid out of swollen tissue, creates a less hospitable environment for bacteria, and promotes healing in the cells that line your mouth. Research on gingival cells found that a concentration of about 1.8% saline, roughly one teaspoon of salt dissolved in a cup (250 ml) of warm water, supported wound healing in lab conditions.
Swish the solution gently around your mouth for about two minutes, then spit it out. Doing this three times a day is a reasonable frequency. It will sting briefly on contact with the ulcer, but the discomfort fades quickly. You can also try a rinse made from a half-teaspoon of baking soda in a cup of water, which neutralizes acids that irritate the sore.
Over-the-Counter Pain Relief
OTC numbing gels and pastes containing benzocaine are widely available at pharmacies. Apply a small amount directly to the ulcer up to four times a day. The gel creates a temporary barrier over the sore while numbing the area, making it easier to eat and talk. Benzocaine lozenges are another option: dissolve one slowly in your mouth every two hours as needed.
Protective pastes that don’t contain a numbing agent can also help. These form a film over the ulcer, shielding it from further irritation by food, teeth, and saliva acids. Look for products labeled as oral wound rinses or protective oral pastes at the pharmacy counter. Some contain ingredients that both coat the sore and reduce inflammation.
Honey as a Treatment
Applying honey directly to a mouth ulcer is more than a folk remedy. A randomized controlled trial comparing honey to a topical corticosteroid paste and a plain oral base found that honey significantly outperformed both in reducing ulcer size, pain duration, and redness. No side effects were reported in the honey group.
Use a clean finger or cotton swab to dab a small amount of raw honey onto the ulcer several times a day, especially after meals. The honey’s natural antimicrobial properties and thick consistency help protect the wound while it heals.
Prescription Options for Stubborn Ulcers
If your ulcer is large, unusually painful, or keeps coming back, a doctor or dentist can prescribe a topical corticosteroid paste. These work by stabilizing cell membranes in the damaged tissue and blocking the release of enzymes that would otherwise extend the inflammation into surrounding healthy tissue. The result is less swelling, less pain, and a better environment for healing.
Another clinical option is chemical cauterization. A doctor applies silver nitrate directly to the ulcer, turning it white on contact. In a randomized controlled trial, 70% of patients treated with silver nitrate had significant pain reduction within one day, compared to just 11% in the placebo group. Healing time wasn’t shortened, but the rapid and lasting pain relief makes it a practical choice for people with infrequent but painful ulcers. The procedure is simple and has no reported side effects.
What Causes Mouth Ulcers in the First Place
Understanding your triggers is the most effective long-term strategy. Common causes include physical trauma (biting your cheek, aggressive brushing, or sharp-edged foods like chips and crackers), stress, hormonal changes, and certain acidic or spicy foods.
Nutritional deficiencies play a real role. People with recurrent mouth ulcers are more likely to have low blood levels of vitamin B12 and folate, and research shows they also tend to consume less of these nutrients in their diet. Iron deficiency has been identified as a factor as well. If you get mouth ulcers frequently, it’s worth looking at whether you’re eating enough leafy greens, legumes, eggs, meat, and fortified cereals, all good sources of B12, folate, and iron.
Certain systemic conditions also cause recurrent oral ulcers. Celiac disease, Crohn’s disease, and Behçet’s disease can all present with mouth sores as an early or ongoing symptom. If your ulcers are frequent, severe, or come with other symptoms like digestive issues, joint pain, or genital sores, these conditions are worth investigating with your doctor.
Preventing Recurrence
One of the simplest changes you can make is switching to a toothpaste that doesn’t contain sodium lauryl sulfate (SLS), the foaming agent in most standard toothpastes. A systematic review of crossover trials found that using SLS-free toothpaste significantly reduced the number of ulcers, the duration of each ulcer, the number of episodes, and pain levels across all four measures studied. Many brands now sell SLS-free versions, often marketed for sensitive mouths.
Beyond toothpaste, keep a mental list of your personal triggers. If ulcers tend to follow stressful weeks, certain foods, or your menstrual cycle, you can plan ahead with preventive rinses or dietary adjustments. Use a soft-bristled toothbrush, eat slowly to avoid accidental bites, and if a dental appliance or rough tooth edge keeps irritating the same spot, get it addressed.
When a Mouth Ulcer Needs Medical Attention
Any mouth ulcer that hasn’t healed after three weeks warrants a professional evaluation. Cancer Research UK’s referral guidelines specify that an unexplained mouth ulcer lasting three weeks or more should prompt an urgent specialist referral to rule out oral cancer. This doesn’t mean every persistent ulcer is cancer. Most aren’t. But a three-week threshold is the standard cutoff because common canker sores almost always resolve well before that point.
Other signs worth getting checked include ulcers that are unusually large (over 10 mm), ulcers accompanied by a hard or thickened area in the mouth, sores that keep recurring in the exact same spot, or ulcers paired with unexplained weight loss, difficulty swallowing, or persistent hoarseness. A dentist or doctor can examine the sore and, if needed, take a small tissue sample to confirm what’s going on.