Mouth ulcers, also called canker sores, are small, shallow sores inside your mouth. Most heal on their own in 7 to 14 days. You cannot cure them instantly, but you can speed up healing and reduce pain with simple home remedies. Over-the-counter treatments and saltwater rinses are the most reliable options. Avoid acidic foods and sharp snacks while the sore heals.
What Actually Causes Mouth Ulcers?
Mouth ulcers are not the same as cold sores. Cold sores come from the herpes virus and appear on the outside of your lips. Mouth ulcers appear inside your mouth — on your cheeks, gums, tongue, or soft palate. They are not contagious.
Doctors do not know the exact cause in every case. But several triggers are well-documented. Minor injury is the most common cause. You bite your cheek. A sharp piece of food scratches your gum. Your toothbrush slips. That small wound turns into an ulcer.
Other triggers include stress, hormonal changes, and certain foods. Acidic foods like citrus fruits, tomatoes, and pineapple are frequent culprits. Toothpastes containing sodium lauryl sulfate may also trigger ulcers in some people. A 2012 study in Oral Diseases found that people who switched to SLS-free toothpaste had fewer outbreaks.
Nutritional deficiencies play a role too. Low levels of vitamin B12, folic acid, iron, or zinc are linked to recurrent mouth ulcers. One study published in Journal of Oral Pathology & Medicine found that nearly 30% of people with recurrent ulcers had a deficiency in one or more of these nutrients.
How To Cure A Mouth Ulcer Home Remedies Treatments That Actually Work
Let’s be direct about what the evidence supports. No home remedy will make a mouth ulcer disappear in an hour. But several treatments can significantly reduce pain and shorten healing time.
Saltwater rinse is the most studied and recommended home treatment. Dissolve half a teaspoon of salt in a cup of warm water. Swish it in your mouth for 30 seconds, then spit it out. Do this three to four times a day. Saltwater creates an environment that is hard for bacteria to survive in. It also reduces inflammation. The American Dental Association lists saltwater rinses as a safe and effective home treatment for mouth sores.
Baking soda paste works similarly. Mix a small amount of baking soda with a few drops of water until it forms a paste. Apply it directly to the ulcer. Leave it on for one to two minutes, then rinse. Baking soda neutralizes acids in your mouth and may reduce irritation.
Honey has real antimicrobial properties. A 2014 study in Quintessence International found that honey applied four times daily reduced ulcer size and pain more effectively than a standard over-the-counter treatment. Use raw, unprocessed honey if possible. Apply a small dab directly to the sore.
Aloe vera gel is another option with decent evidence. Aloe has anti-inflammatory and wound-healing properties. Apply pure aloe vera gel directly to the ulcer three times a day. Avoid products with added sugar or artificial ingredients.
| Remedy | What the Evidence Says | How to Use It |
|---|---|---|
| Saltwater rinse | Strong evidence. Reduces bacteria and inflammation. | ½ tsp salt in 1 cup warm water. Rinse 3-4x daily. |
| Baking soda paste | Moderate evidence. Neutralizes acid and soothes. | Mix with water. Apply 1-2 minutes. Rinse. |
| Honey | Moderate evidence. Antimicrobial and reduces size. | Apply raw honey directly. 4x daily. |
| Aloe vera gel | Moderate evidence. Reduces inflammation. | Apply pure gel. 3x daily. |
| Over-the-counter gels | Strong evidence. Contain benzocaine or lidocaine. Numb pain. | Apply a small amount directly. Follow label instructions. |
What Should You Avoid When You Have a Mouth Ulcer?
What you do not put in your mouth matters as much as what you do. Certain foods and habits will make a mouth ulcer worse. Avoiding them is one of the most effective things you can do.
Acidic foods are the biggest problem. Oranges, lemons, grapefruit, tomatoes, strawberries, and pineapple all contain acids that directly irritate the raw tissue of an ulcer. Avoid them until the sore heals. The same goes for vinegar-based dressings and pickled foods.
Spicy foods are another common trigger. Chili peppers, hot sauce, curry, and even black pepper can cause significant pain when they touch an open sore. Stick to bland, mild foods while the ulcer is present.
Crunchy, sharp foods like chips, pretzels, toast, and nuts can physically scrape the ulcer. This makes it larger and slows healing. Soft foods are better — yogurt, mashed potatoes, oatmeal, smoothies.
Do not touch the ulcer with your tongue or fingers. Your tongue is a muscle that moves constantly. Poking at the sore will keep it irritated. Fingers introduce bacteria. Leave it alone.
Avoid alcohol-based mouthwashes. They dry out the tissue and can sting badly. The National Institutes of Health recommends using a non-alcoholic mouthwash or a simple saltwater rinse instead.
Do Over-the-Counter Treatments Work Better Than Home Remedies?
Over-the-counter treatments are a solid option, especially for pain relief. Products containing benzocaine or lidocaine numb the area temporarily. This makes eating and talking much easier. Brands like Orajel and Anbesol are common examples. They work within seconds and last for 15 to 30 minutes.
Some OTC products also contain ingredients that form a protective barrier over the ulcer. These films or patches stick to the sore and protect it from food and saliva. They can reduce pain significantly and may help the ulcer heal faster by keeping it clean.
For most people, home remedies like saltwater rinses and baking soda paste work about as well as OTC products for healing. The main advantage of OTC treatments is better pain control. If pain is keeping you from eating or sleeping, an OTC numbing gel is worth using.
A 2016 review in Clinical, Cosmetic and Investigational Dentistry compared various treatments for mouth ulcers. The authors found that no single treatment was clearly superior. The best approach depends on what works for you personally. Many people combine a saltwater rinse with an OTC numbing gel for the best results.
When Should You See a Doctor or Dentist?
Most mouth ulcers do not need medical attention. But some situations do require a professional evaluation. The American Academy of Oral Medicine suggests seeing a doctor or dentist if any of the following apply:
- The ulcer lasts longer than two weeks without healing.
- The ulcer is unusually large — bigger than half an inch across.
- You get new ulcers before old ones heal.
- The pain is severe enough to interfere with eating or drinking.
- The ulcer spreads or you develop a fever.
- You have frequent outbreaks — several per month.
In some cases, a doctor may prescribe a corticosteroid paste like triamcinolone acetonide. This reduces inflammation more effectively than home remedies. For severe or recurrent cases, doctors sometimes prescribe mouth rinses containing dexamethasone or lidocaine.
If you have recurrent ulcers, your doctor may order blood tests. They will check for deficiencies in vitamin B12, folic acid, iron, and zinc. Correcting a deficiency often reduces the frequency of outbreaks significantly. A 2017 study in Journal of the American Board of Family Medicine found that supplementing with vitamin B12 reduced outbreak frequency by 74% in people with recurrent mouth ulcers.
Some people with recurrent ulcers have an underlying condition like celiac disease, Crohn’s disease, or Behçet’s disease. These are less common but worth considering if ulcers are frequent and severe. Your doctor can help determine if further testing is needed.
Common Misconceptions About Mouth Ulcer Treatments
Several viral remedies for mouth ulcers have little to no evidence behind them. Knowing what does not work is just as important as knowing what does.
Rubbing aspirin directly on the ulcer is a dangerous myth. Aspirin is an acid. Putting it directly on an open sore causes a chemical burn. It will hurt more and damage the tissue. Never do this. If you want pain relief, swallow an over-the-counter pain reliever like ibuprofen or acetaminophen. Do not apply it topically.
Alcohol or hydrogen peroxide applied directly to the ulcer is another bad idea. Both substances damage healthy tissue and slow healing. Hydrogen peroxide can be used as a diluted mouth rinse — mix equal parts 3% hydrogen peroxide and water — but do not apply it full strength or use it more than once a day.
Garlic or onion slices placed on the ulcer are widely claimed to help. There is no clinical evidence that this works. Garlic has antimicrobial properties in a lab setting, but putting a raw garlic clove on a mouth ulcer causes intense burning and irritation. It does more harm than good.
Vitamin C tablets placed directly on the ulcer is another myth. Vitamin C is acidic. Putting a tablet on an open sore will sting badly and may damage tissue. If you want more vitamin C, eat whole foods or take a supplement by mouth. Do not apply it topically.
Milk of magnesia is sometimes recommended as a home remedy. Some people report that it helps dry out the ulcer. Evidence is very limited. It is not harmful, but it is not a proven treatment either.
Frequently Asked Questions
How long does a mouth ulcer take to heal with home remedies?
Most mouth ulcers heal within 7 to 14 days. Home remedies can reduce pain and may shorten healing time by a few days.
Can I pop or drain a mouth ulcer?
No. Mouth ulcers are not blisters. There is nothing to drain. Picking at them makes them larger and slower to heal.
Is salt water or baking soda better for mouth ulcers?
Both work well. Salt water reduces bacteria and inflammation. Baking soda neutralizes acid. Use whichever you prefer.
What vitamin deficiency causes mouth ulcers?
Low levels of vitamin B12, folic acid, iron, or zinc are linked to recurrent mouth ulcers. A blood test can check for deficiencies.

