Most mouth ulcers heal on their own within one to two weeks, but you can speed up relief and reduce pain with a few proven strategies. These small, round sores (white or yellow with a red border) appear inside the mouth on the cheeks, lips, tongue, or gums. While they’re rarely serious, they can make eating and talking miserable.
Mouth Ulcers vs. Cold Sores
Before treating a mouth ulcer, make sure that’s what you’re dealing with. The easiest way to tell the difference is location. Mouth ulcers (canker sores) appear inside the mouth, usually as a single round white or yellow sore with a red border. Cold sores (fever blisters) appear outside the mouth, typically as clusters of small fluid-filled blisters around the border of the lips. Cold sores are caused by herpes simplex virus and require different treatment, so if your sore is on the outside of your lips, the advice below won’t apply.
Over-the-Counter Pain Relief
The fastest way to manage pain is a topical numbing gel or liquid containing 20% benzocaine, an oral anesthetic sold under brands like Orajel and store-brand equivalents. You apply it directly to the sore, and it temporarily numbs the area so you can eat and drink more comfortably. These products are designed specifically for canker sores and minor mouth irritation.
Antiseptic mouthwashes containing hydrogen peroxide or chlorhexidine can help keep the ulcer clean and prevent secondary infection, which may otherwise slow healing. Over-the-counter protective pastes that form a barrier over the sore can also reduce irritation from food and your teeth rubbing against it.
Home Remedies That Help
A simple saltwater rinse is one of the most effective home treatments. Dissolve half a teaspoon of salt in a cup of warm water and swish it around your mouth for 30 seconds before spitting it out. This draws fluid from the swollen tissue and creates a less hospitable environment for bacteria. You can repeat this several times a day.
Baking soda rinses work similarly. Mix one teaspoon of baking soda in half a cup of warm water and use it as a rinse. Baking soda neutralizes acids in the mouth that can irritate the sore. Applying a small amount of honey directly to the ulcer several times a day can also help, as honey has natural anti-inflammatory properties and creates a protective coating over the wound.
While you’re healing, avoid foods that aggravate the sore. Acidic foods like citrus fruits, tomatoes, and vinegar-based dressings are common culprits. Spicy foods, crunchy chips, and very hot drinks can all irritate the ulcer and delay recovery.
When Ulcers Keep Coming Back
If you get mouth ulcers repeatedly, a nutritional deficiency may be driving the cycle. Low levels of vitamin B12, folate, and iron are all linked to recurrent ulcers. B12 deficiency is particularly common and often goes unrecognized. If your ulcers keep returning every few weeks or months, a blood test can check for these deficiencies. Correcting a B12 or folate shortfall through diet or supplements often reduces how frequently ulcers appear.
Good food sources of B12 include meat, fish, eggs, and dairy. Folate is found in leafy greens, beans, and fortified cereals. Iron comes from red meat, spinach, and lentils. If blood tests confirm a deficiency, supplementation at the right dose can make a noticeable difference in ulcer frequency.
Switch Your Toothpaste
Many toothpastes contain sodium lauryl sulfate (SLS), a foaming detergent also used in shampoos and soaps. SLS is effective at cleaning teeth and killing microbes, but it can irritate the soft tissue inside your mouth, especially if you’re prone to ulcers. Switching to an SLS-free toothpaste is one of the simplest changes you can make. Several brands market themselves as SLS-free, and they’re widely available at pharmacies and grocery stores. Some people notice a significant drop in ulcer frequency within a few weeks of making the switch.
Other Common Triggers
Mouth ulcers often follow a pattern, and identifying your personal triggers can help you prevent them. Physical trauma is one of the most common causes: biting the inside of your cheek, brushing too hard, or irritation from braces or ill-fitting dentures. Using a soft-bristled toothbrush and being gentle around the gums reduces this kind of damage.
Stress is another well-established trigger. Many people notice ulcers flare up during high-pressure periods at work or school. Hormonal changes can also play a role, with some women experiencing ulcers around their menstrual cycle. You can’t always avoid these triggers, but recognizing them helps you act early with rinses or protective gels before a developing sore gets worse.
Prescription Options for Severe Cases
If over-the-counter treatments aren’t providing enough relief, a doctor or dentist can prescribe stronger options. A steroid-based mouthwash can reduce inflammation and pain for more extensive ulceration. These rinses are swished around the mouth and spit out, delivering anti-inflammatory medication directly to the affected tissue.
Silver nitrate cauterization is another option sometimes used in clinical settings. A small stick is applied directly to the ulcer to chemically seal it. The application itself is quite painful, and it can actually cause additional tissue damage that slows healing, so it’s generally reserved for stubborn sores where the main goal is immediate pain relief rather than faster recovery.
Signs Something More Serious Is Going On
Most mouth ulcers are harmless and heal without treatment. But certain patterns warrant a call to your doctor or dentist:
- A sore that lasts three weeks or longer
- New ulcers appearing before old ones have healed
- Sores that are unusually large
- Painless mouth sores (most ulcers hurt, so a painless one is actually more concerning)
- Ulcers on the outer part of your lips rather than inside the mouth
- Pain that doesn’t respond to any treatment
- Accompanying fever or diarrhea
Persistent or unusual ulcers can occasionally signal underlying conditions like celiac disease, inflammatory bowel disease, or in rare cases, oral cancer. A healthcare provider can examine the sore, run blood work if needed, and rule out anything that requires further investigation.