How To Get Rid of Canker Sores

When you feel the pain of a canker sore, there are remedies you can use to help ease the discomfort and possibly speed the healing process. Try these at-home and over-the-counter (OTC) treatments for minor canker sores and know when you should see your dentist for the problem.

At-home and OTC canker sore remedies
Illustration by Brianna Gilmartin, Verywell

How Long Canker Sores Last

Canker sores usually heal on their own within a week or two. The home remedies described below may help take some of the sting out of the sores by reducing inflammation and bacteria and enhancing healing.

There are also a variety of products you can buy without a prescription that can help relieve pain temporarily and speed healing. These come in different forms, including pastes, gels, and liquids, and they work best if you apply them directly to each canker sore as soon as it appears. Your pharmacist, doctor, or dentist can offer advice on which may work best for you.

What Is a Canker Sore?

Simple canker sores, also called aphthous ulcers, are among the most common types of oral ulcers. They are usually small and shallow and develop inside the mouth and at the base of the gums. They are different from cold stores, which occur on the lips. Canker sores can't be transmitted to anyone else, but they can hurt for a week or two until they heal, usually on their own. Home remedies may help reduce pain and speed the healing process.

The exact cause of canker sores is unknown, but stress and minor injury inside the mouth are believed to be triggers. Some foods, such as acidic fruits and vegetables, may provoke canker sores or make existing sores worse, as can certain medications.  

Saltwater and Sodium Bicarbonate 

If you rinse your mouth several times a day with salt water or gargle with a solution of salt water, you may be able to improve the healing of cancer sores while promoting healthy gums. (Avoid putting salt directly on the ulcer.) Bear in mind that the salt solution may initially sting when it comes into contact with the ulcer.

To make the salt water solution, mix one teaspoon of salt in one cup of warm water. Swish the solution in your mouth for 30 seconds, then spit the solution out.

In addition to salt, 1/2 teaspoon baking soda (sodium bicarbonate) may be added to the saline solution. Create a paste by mixing baking soda with small drops of water until a thick consistency result. Use this paste to cover the canker sores, which will help relieve pain.

These methods may be repeated as often as needed. Saline and sodium bicarbonate both help the mouth heal quickly by gently reducing the alkalinity and bacteria in the mouth.

Hydrogen Peroxide Solution

Mix one part hydrogen peroxide with one part water. Use a cotton swab to dab the solution directly onto the canker sores. Do not swallow the solution. Hydrogen peroxide is an antiseptic that will help reduce the number of bacteria in the mouth.


Honey has been shown to have healing properties for canker sores. Direct applications of honey several times a day to each sore can help reduce the number of days of pain, as well as ulcer size and redness. 

You can also use honey as a canker sore remedy by mixing it in tea, such as chamomile, and drinking several cups over the course of a day. Honey that has not been pasturized is recommended.

Milk of Magnesia

Used frequently as an aide to relieve constipation and as an antacid, milk of magnesia is a liquid suspension of magnesium hydroxide. Dab milk of magnesia directly onto the canker sores with a cotton swab, three to four times a day.

This method is recommended after using the hydrogen peroxide solution. Milk of magnesia may help reduce the pain and help speed the healing process.

Coconut Oil

Coconut oil and its lauric acid component help fight some harmful bacteria in the mouth and may enhance healing of canker sores. Daily swishing with about a tablespoon of this oil in the mouth, a practice known as oil pulling, may also reduce dental plaque. 

In addition to its beneficial effects on oral health, oil pulling is also believed to enhance overall health. However, oil pulling is not a substitute for dental care and is not currently recommended by American dental association.

Alum Powder

Alum powder (crystallized potassium aluminum sulfate) is a food additive often used to help keep pickled fruits and vegetables fresh. It is also an ingredient in baking powder. You can buy it in the spice section of your grocery store.

One study of 50 young women found that alum significantly decreased the size of oral ulcers and reduced pain severity. The average period of full ulcer healing was about 7 days for women treated with alum and about 12 days for women who were not treated.

You can create a paste by mixing a pea-sized drop of alum with a drop of water. Apply the mixture directly to each canker sore and let it sit for at least one minute. Then rinse. Do this daily until you see results.

Apple Cider Vinegar Rinse

Apple cider vinegar has bacteria fighting properties that may help heal canker sores. To create a rinse, mix a teaspoon of the vinegar into a cup of water and swish the solution around your mouth for up to a minute. Then spit and rinse your mouth thoroughly. 

Because vinegar can damage tooth enamel, it's best to rinse with apple cider vinegar just once a day. Keep in mind that the solution may sting, so it if causes pain, try a different remedy. 

Liquid Antihistamine

Benadryl (diphenhydramine) liquid allergy medicine may be used as an oral rinse by mixing one part milk of magnesia and one part diphenhydramine together. Rinse with the solution for one minute, then fully spit out the solution. Take care to avoid swallowing this mixture.

OTC Oral Care Products and Rinses

The dental care section of your supermarket or drug store has several non-prescription options.

  • Antiseptic mouth rinses contain ingredients intended to help heal mouth sores by reducing the number of bacteria in the mouth.
  • Oral care products that numb painful areas in the mouth are also useful when treating canker sores.
  • Products such as gels, paste, and rinses that are specifically marketed for mouth sores may provide pain relief and help speed the healing process.

It is important that you follow the manufacturers' instructions closely when using over-the-counter products.

When to See a Dentist for Treatment

Canker sores that are classified as major, or are considered herpetiform canker sores, may require treatment from your dentist. Common treatments include oral medicaitons, and (rarely) corticosteroids.

Consult your dentist when canker sores do not heal after 14 days, are accompanied by a fever, or appear to be infected.

Oral Medications

Prescription medication may be necessary for treating serious canker sores that have developed into secondary infections.

Tetracycline suspension (liquid) may be prescribed with instructions to hold the medicine in the mouth for two to five minutes before swallowing. Tetracycline is typically not prescribed for children as it has been shown to cause permanent discoloration in developing teeth.

Zovirax (acyclovir) is an antiviral drug that may be prescribed for cases where there are multiple, very painful canker sores.


Although rare, corticosteroids such as prednisone and dexamethasone may be prescribed as a treatment for canker sores. Dexamethasone suspension (liquid) may be prescribed for use as an oral rinse with instruction to fully spit out after a determined time.

A Word From Verywell

Keep in mind that even though they are painful, canker sores tend to heal well on their own. Use these methods for relief and see your dentist for any non-healing canker sores.

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  2. Madeswaran S, Jayachandran S. Sodium bicarbonate: A review and its uses in dentistryIndian Journal of Dental Research. 2018;29(5):672-677. doi:10.4103/ijdr.IJDR_30_17

  3. Rashed HT. Evaluation of the effect of hydrogen peroxide as a mouthwash in comparison with chlorhexidine in chronic periodontitis patients: A clinical study. J Int Soc Prev Community Dent. 2016;6(3):206–212. doi:10.4103/2231-0762.183114

  4. Subiksha PS. Various Remedies for Recurrent Aphthous Ulcer-A Review. J Pharm Sci & Res. 2014;6(6):251-253. 

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