Most mouth sores heal on their own within one to two weeks, but you can speed things up and cut the pain significantly with a few simple treatments. The right approach depends on what type of sore you’re dealing with, since canker sores (inside the mouth) and cold sores (outside, around the lips) have different causes and respond to different remedies.
Figure Out What Kind of Sore You Have
Canker sores are single, round ulcers with a white or yellow center and a red border. They show up inside the mouth, usually on the inner cheeks, lips, or tongue. Nobody knows exactly what causes them, but common triggers include mouth injuries (like biting your cheek), stress, smoking, and deficiencies in folic acid, iron, or vitamin B12.
Cold sores look completely different. They appear as clusters of small, fluid-filled blisters around the border of your lips, not inside the mouth. They’re caused by herpes simplex virus type 1 (HSV-1) and are contagious. If your sore is a cluster of blisters on or near your lips, you’ll need an antiviral treatment rather than the remedies below, which focus on canker sores and general mouth ulcers.
Salt Water Rinse: The Simplest Fix
A warm salt water rinse is the easiest and cheapest treatment you can start right now. Mix 1 teaspoon of salt into 8 ounces of warm water until it dissolves. If that stings too much, cut back to half a teaspoon. Swish it around the sore for 30 seconds, then spit. Do this two to three times a day.
Salt water works as a mild antiseptic, pulling bacteria away from the ulcer and reducing inflammation. Studies show that rinses in the 0.9% to 1.8% salt range promote gum health and wound recovery. It won’t taste great, but it reliably soothes pain and helps the sore close faster.
Over-the-Counter Pain Relief
Oral gels and pastes containing benzocaine are widely available at pharmacies. Benzocaine is a topical numbing agent that blocks pain signals from nerve endings at the sore site. You apply a small amount directly to the ulcer, and it provides temporary relief within minutes. Look for products specifically labeled for mouth sores or oral pain.
For best results, avoid eating or drinking for at least 30 minutes after applying any topical mouth treatment. This keeps the medication in contact with the sore longer, which makes a noticeable difference in how well it works.
Honey Works Surprisingly Well
If you prefer a natural option, raw honey is worth trying. In a randomized clinical trial comparing honey to a standard prescription steroid paste, both treatments produced identical healing outcomes. Patients using honey three times a day saw their ulcers shrink by about 59% within the first few days, with complete healing by the end of the study period. Pain scores dropped by roughly 48% early on and reached zero by the final visit.
Honey actually outperformed the steroid on one measure: it reduced burning sensation by 55% compared to 30% for the prescription treatment, a statistically meaningful difference. To use it, dab a small amount of honey directly onto the sore three times a day. Let it sit without eating or drinking afterward.
Prescription Options for Severe or Recurring Sores
When sores are large, extremely painful, or keep coming back, a dentist or doctor can prescribe stronger treatments. The first-line prescription is typically a steroid mouth rinse, which reduces inflammation, alters the course of the ulcer, and speeds healing. Steroid ointments and pastes applied directly to the sore are another common option.
People with frequent, severe outbreaks may need a course of oral steroids at the first sign of symptoms, sometimes combined with an antimicrobial mouthwash. One thing to watch for with steroid treatments: they can occasionally lead to a yeast overgrowth in the mouth, so your provider will monitor for that. For the most stubborn cases, specialists may turn to immune-suppressing medications.
Preventing Sores From Coming Back
Switch Your Toothpaste
Many common toothpastes contain sodium lauryl sulfate (SLS), a foaming agent that can irritate the lining of your mouth. A systematic review published through the American Dental Association found that people who switched to SLS-free toothpaste developed significantly fewer ulcers, experienced shorter ulcer duration, had fewer recurring episodes, and reported less pain. The data showed roughly one fewer ulcer per cycle on average. SLS-free toothpastes are easy to find; check the ingredients list or look for brands that specifically advertise “SLS-free” on the label.
Address Nutritional Gaps
Deficiencies in vitamin B12, iron, and folic acid are known triggers for recurrent canker sores. Interestingly, research on vitamin B12 supplementation suggests it may help even when blood levels of B12 are already normal, hinting that the benefit might involve something beyond simply correcting a deficiency. If you get canker sores frequently, it’s worth looking at whether your diet is low in these nutrients. Leafy greens, legumes, eggs, meat, and fortified cereals are good sources.
Reduce Physical Triggers
Biting the inside of your cheek, aggressive brushing, sharp edges on braces or dental work, and acidic or spicy foods can all trigger new sores or reopen healing ones. Using a soft-bristled toothbrush and being mindful of rough foods during an active outbreak helps the healing process considerably. Stress is another well-documented trigger, so recurring sores sometimes track with high-pressure periods in your life.
Signs a Mouth Sore Needs Professional Attention
Most canker sores resolve within two weeks without any treatment at all. But the NHS recommends seeing a dentist or doctor if a mouth ulcer lasts longer than three weeks, looks different from sores you’ve had before (especially if it’s unusually large or located near the back of your throat), or becomes increasingly painful, red, or starts bleeding, which can signal an infection. Sores that don’t heal on a normal timeline can occasionally point to something more serious, so a persistent ulcer is always worth getting checked.