Canker Sore Remedies That Actually Work

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

Saltwater and Sodium Bicarbonate 

Mix 1 teaspoon salt in 1 cup 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.

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 will help reduce the pain and help speed the healing process.

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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Article Sources
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Additional Reading
  • Canker Sore. MedlinePlus.

  • Edgar NR, Saleh D, Miller RA. Recurrent Aphthous Stomatitis: A Review. The Journal of Clinical and Aesthetic Dermatology. 2017;10(3):26-36.