A mouth ulcer is a small, painful open sore on the inside of your cheeks, lips, gums, tongue or the roof of your mouth. Most mouth ulcers are canker sores, which aren’t contagious and heal on their own within one to two weeks. To treat a mouth ulcer at home, rinse with salt water, dab honey or aloe vera on the sore, and avoid spicy, salty and acidic food while it heals. If mouth ulcers keep coming back, it’s worth looking at what’s happening inside your body, from your diet to your stress levels.
The short version
- Most mouth ulcers are canker sores and heal within one to two weeks.
- Salt water, honey, aloe vera and coconut oil pulling are simple home remedies that help.
- Stress, sugar, alcohol, low B12 and gut problems are common reasons they keep coming back.
- A mouth ulcer in a baby or toddler should be checked by a GP.
- Any ulcer that hasn’t healed in three weeks needs a dentist to look at it.
What Is a Mouth Ulcer?
Mouth ulcer is the general name for any open sore inside the mouth. The most common type by far is the canker sore, also called an aphthous ulcer. The American Dental Association describes these as small, creamy white ulcers with a red border. They’re not contagious and can’t be passed on by kissing or sharing a cup. If you want to go deeper into this type, our canker sore treatment guide covers everything from the stages to over the counter options.
Not every sore in the mouth is a canker sore, though. Mouth sores can also come from bacterial, viral or fungal infections, which is why it helps to know the possible causes.
Mouth Ulcer Causes
Canker sores
These are the typical round, shallow ulcers with a white or yellow base. Doctors still don’t know exactly why they happen, but small injuries in the mouth and certain foods are known triggers.
An imbalance in your body
In my experience, most mouth ulcers come from an imbalance of bacteria or fungus that your body can’t fully fight off, so it comes out as an ulcer. Research is starting to agree that bacteria matter: an analysis of 14 studies found that people with canker sores have a different mix of mouth bacteria than people without them. Too much sugar, alcohol or bread can push your system further out of balance.
Stress
Many people notice that a mouth ulcer shows up after a stressful week, an exam or a bad night’s sleep. The American Dental Association lists stress and fatigue as factors linked to canker sores. Stress weakens your defences, and that’s exactly when an imbalance can come to the surface.
Injury
Biting your cheek, a sharp tooth, braces, a rough filling, a rubbing denture or brushing too hard can all leave a sore that turns into an ulcer.
Low vitamin B12, iron or folate
Low levels of these nutrients are linked with recurring mouth ulcers. A simple blood test from your GP can check.
Gut conditions, including Crohn’s disease
Mouth ulcers can be a sign of a gut problem. In people with inflammatory bowel disease, aphthous ulcers are the most common mouth symptom, and they can show up in Crohn’s disease before the gut symptoms do. Recurring ulcers are also linked with gluten sensitivity and coeliac disease.
Viruses and thrush
Groups of small blisters that burst into ulcers can be caused by a virus, such as the herpes virus or hand, foot and mouth disease, especially in children. A white coating that wipes off to leave a red patch can be oral thrush, a yeast infection. These need a different approach, so see a GP or dentist. Not sure whether you have a cold sore? Here’s how to tell a cold sore or a canker sore apart.
First Step for Recurring Mouth Ulcers: Look at Your Lifestyle
If you keep getting mouth ulcers, don’t just treat each one as it comes. Diagnose your lifestyle first. Too much alcohol, bread or sugar can put your system in an unregulated state, and a detox from these common triggers might be your first step to avoiding mouth sores.
- Cut back on sugar, soft drinks and white bread.
- Take a break from alcohol for a few weeks.
- Eat more vegetables, protein and fermented foods like plain yogurt.
- Build in real rest after stressful periods.
- Keep a short diary of what you ate and how you slept before each new ulcer.
Finding it hard to stay away from sugar?
Gluco-Control is a plant based supplement with enzymes, mushroom extracts and probiotics, taken before meals. It’s designed to support healthy blood sugar and curb sweet cravings, which can make cutting back on sugar a lot easier while you rebalance.
This is an affiliate link. If you buy through it, Home Remedy Shop may earn a small commission at no extra cost to you. A supplement works alongside dietary changes, not instead of them.
For the full detox plan, including my morning apple cider vinegar shot and a gentle zeolite option, see our canker sore treatment guide.
10 Home Remedies for Mouth Ulcers
These natural and herbal remedies ease the pain and help a mouth ulcer heal. Pick two or three and use them consistently for a few days.
1. Honey
Honey is one of the best studied home remedies for mouth ulcers. In one trial, honey shrank ulcers and eased pain and redness faster than a steroid cream and a protective paste. Dab raw or manuka honey on the ulcer after meals and before bed. Never give honey to a baby under one year old.
2. Salt water rinse
Dissolve half a teaspoon of salt in a glass of warm water, swish for 30 seconds and spit. Do it three or four times a day, especially after eating. It keeps the ulcer clean and calms the area.
3. Baking soda rinse
Baking soda neutralises acid in the mouth. Stir a teaspoon into half a glass of warm water and rinse, or dab a little baking soda paste on the ulcer. It’s a traditional remedy that many people find soothing.
4. Coconut oil pulling
Oil pulling helps rebalance the bacteria in your mouth. Swish a tablespoon of coconut oil around for 10 to 15 minutes each morning, then spit it into the bin and rinse. A study found that coconut oil pulling reduced harmful mouth bacteria about as well as a chlorhexidine mouthwash. You can also dab a little coconut oil on the ulcer to protect it.
5. Aloe vera gel
Aloe vera calms and coats the sore. In a recent trial, aloe vera gel worked about as well as a steroid paste for minor mouth ulcers. Use pure, food grade gel without alcohol and apply it two or three times a day.
6. Chamomile tea
Chamomile has been used for mouth sores for generations because it’s gentle and calming. Brew a cup of chamomile tea, let it cool and use it as a mouth rinse, or press the cooled tea bag against the ulcer for a few minutes. It’s a traditional herbal remedy, so see it as comfort care.
7. Sage rinse
Sage is another traditional herb for the mouth and throat. Pour boiling water over a few fresh sage leaves or a teaspoon of dried sage, let it cool and rinse two or three times a day. It’s gentle enough to use daily while the ulcer heals.
8. Plain yogurt
Plain, unsweetened yogurt with live cultures is soft and cool on a painful mouth, and it brings friendly bacteria that support a healthier balance. Eat a small bowl once or twice a day. Skip the sweetened versions, since sugar works against you here.
9. Vitamin B12
If you get mouth ulcers often, vitamin B12 is worth trying. In a double blind trial, 74% of people taking B12 every night became ulcer free, compared with 32% on a placebo, and it worked even when B12 levels were normal. Give it a few months.
10. SLS free toothpaste
The foaming agent in most toothpastes, sodium lauryl sulfate, can irritate the lining of the mouth. There’s limited evidence that an SLS free toothpaste helps people with recurring ulcers, but it’s an easy swap to try.
How to Treat a Mouth Ulcer Overnight
A mouth ulcer can’t fully heal overnight, because the tissue needs time to rebuild. But you can make the next morning a lot more comfortable. Rinse with warm salt water after dinner, brush gently with an SLS free toothpaste, then dab honey or aloe vera gel on the ulcer right before bed. Oil pull with coconut oil when you wake up. Most ulcers feel noticeably better within two or three days.
Mouth Ulcer on the Roof of the Mouth
An ulcer on the roof of the mouth often starts after a burn from hot food or a scrape from crusty bread or crisps. Stick to soft, cool foods and let hot drinks cool down first. Salt water rinses and honey work well here. A painless lump or a patch on the roof of the mouth that doesn’t go away is not a typical ulcer, so have a dentist look at it.
Mouth Ulcers in Babies and Toddlers
Mouth ulcers in infants and young children are often caused by a virus, such as hand, foot and mouth disease or a first herpes infection, or by oral thrush. These can make a little one refuse to eat or drink. See your GP or paediatrician, especially if your child has a fever, isn’t drinking or has fewer wet nappies. Don’t give honey to babies under one year old, and don’t use numbing gels with benzocaine on children under two.
Mouth Ulcer or Mouth Cancer?
Almost all mouth ulcers are harmless and heal within two weeks. Mouth cancer is much rarer, but it’s worth knowing the difference. See a dentist if you notice:
- An ulcer that hasn’t healed in three weeks
- A red or white patch in the mouth that doesn’t go away
- A lump or thickening in the cheek, gum or tongue
- An ulcer that doesn’t hurt but keeps growing
Smoking and heavy drinking raise the risk, which is one more reason to cut back on alcohol.
When to See a Dentist or Doctor
- An ulcer that hasn’t healed in three weeks. See a dentist to have it checked properly.
- Mouth ulcers that keep coming back. Ask your GP for a blood test for vitamin B12, iron and folate.
- Ulcers with stomach pain, diarrhoea, bloating or weight loss. A gastroenterologist can check for Crohn’s disease or coeliac disease.
- Very large ulcers, many at once, or ulcers with a fever. See a dentist or an oral medicine specialist.
- A baby or young child with mouth ulcers who isn’t eating or drinking. See your GP the same day.
Knowing exactly what you’re dealing with is what lets you treat it the right way naturally.
Got a sore on your tongue in particular? Read our guide to a canker sore on the tongue.
Frequently Asked Questions
How do you treat a mouth ulcer at home?
Rinse with warm salt water a few times a day, dab honey or aloe vera gel on the ulcer and avoid spicy, salty and acidic foods. Oil pulling with coconut oil in the morning helps rebalance the bacteria in your mouth.
What causes mouth ulcers?
Most mouth ulcers are canker sores. Common triggers are an imbalance of bacteria your body can’t fully fight off, too much sugar, alcohol or bread, stress, small injuries, low vitamin B12, iron or folate, and gut conditions like Crohn’s disease or coeliac disease.
Can stress cause mouth ulcers?
Yes, stress and tiredness are well known triggers. Many people get a mouth ulcer after a stressful week or a period of poor sleep.
How long does a mouth ulcer last?
Most mouth ulcers heal within one to two weeks. Larger ones can take several weeks. An ulcer that lasts longer than three weeks should be checked by a dentist.
Are mouth ulcers contagious?
Canker sores, the most common type of mouth ulcer, are not contagious. Ulcers caused by a virus, such as herpes or hand, foot and mouth disease, can spread.
This article is for general information and does not replace a diagnosis. If an ulcer doesn’t heal, keeps coming back or you feel unwell, see a dentist or doctor.
