How To Get Rid of Canker Sores

Simple canker sores, also called aphthous ulcers, are among the most common types of ulcers in the mouth. They are usually small and shallow, and develop inside the mouth and at the base of the gums.

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, or medicines can provoke canker sores or make existing ones worse. 

Canker sores are different from cold sores, which occur on the lips and are caused by the herpes virus. Cold sores are contagious, but canker sores are not. But they can be painful.

Home remedies and over-the-counter (OTC) treatments may help reduce pain and speed the healing process. This article outlines some commonly used options and when you should contact your dentist.

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. Home remedies may reduce inflammation and bacteria, making the sores more bearable until they resolve and enhancing healing.

Various over-the-counter pastes, gels, and liquid treatments can also help temporarily relieve pain and speed healing. These 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.

Salt Water and Sodium Bicarbonate 

Saline (salt water) and sodium bicarbonate (baking soda) can help canker sores heal faster by reducing acid levels in your mouth. This creates an environment that makes it harder for bacteria to grow, which can help the healing process.

Salt water rinses can also promote healthy gums. 

Make a saltwater rinse: Never put salt directly on an ulcer. Instead, make a saltwater solution by mixing one teaspoon of salt in one cup of warm water. Swish it in your mouth or gargle it for about 30 seconds, then spit it out. Though it may sting at first, the benefits are worth it.

Create a baking soda paste: Mix baking soda with a small amount of water until it thickens. Put the paste on your canker sore(s).

Repeated as often as needed while your mouth heals.

Putting salt directly on a canker sore can make it worse. Instead, make a salt water solution and gently rinse your mouth with it.

Hydrogen Peroxide Solution

As an antiseptic, hydrogen peroxide can help keep your sore free of bacteria, which will help it heal.

To use, mix one part hydrogen peroxide with one part water. Dab the solution on your canker sore with a cotton swab. Never swallow the hydrogen peroxide solution.


Honey has been shown to have healing properties for canker sores. Direct applications of honey to each sore several times a day 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. Chamomile tea has also been shown to be helpful by itself.

Raw (unpasteurized) honey is recommended.

Milk of Magnesia

Milk of magnesia is a liquid suspension of magnesium hydroxide. It is used frequently as an antacid and to relieve constipation. It can help reduce canker sore pain and help speed the healing process.

The best way to apply milk of magnesia to your canker sore is to use a cotton swab. It can be applied three to four times a day. Some people apply it after rinsing with a hydrogen peroxide solution.

Coconut Oil

Coconut oil contains lauric acid, which can help fight some harmful bacteria in the body.

Daily swishing with about a tablespoon of this oil, a practice known as oil pulling, may help reduce bacteria in the mouth and aid the healing process. 

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.

Research has shown that alum can decrease canker sore size and reduce pain.

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

Apple Cider Vinegar Rinse

Another antibacterial household staple, apple cider vinegar can be used in a rinse to help heal your canker sores.

Mix a teaspoon of the vinegar into a cup of water. Swish the solution around your mouth for up to a minute. Then spit and rinse your mouth thoroughly.

Keep in mind that an apple cider vinegar rinse may sting. If it causes pain, you may want to try a different remedy.

Vinegar is highly acidic, and can damage tooth enamel, so it's best to use this just once a day.

Liquid Antihistamine

Used most often for allergy relief, liquid Benadryl (diphenhydramine) can be used to help heal your canker sores.

Make an oral rinse by mixing one part liquid diphenhydramine and one part milk of magnesia together. Rinse with the solution for one minute, then spit it out. Do not swallow any of the mixture.


If you're looking for canker sore relief, a solution may be as close as your kitchen cupboard or medicine cabinet. Salt water, baking soda, alum, honey, and apple cider vinegar can be used as rinses can soothe your sores. Peroxide, milk of magnesia and even liquid allergy medicine can also be helpful.

OTC Oral Care Products and Rinses

The dental care section of your supermarket or drugstore has several non-prescription options you can consider as well.

  • 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 specifically marketed for mouth sores may provide pain relief and help speed the healing process. These come in gel, paste, and rinse forms.

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

When to See a Dentist

If you have a canker sore that doesn't respond to home remedies or over-the-counter treatment, or that lasts for more than 14 days, it may be time to seek additional help.

Call your dentist if you have:

  • A canker sore that grows in size or is unusually large
  • Frequent outbreaks of canker sores
  • Extreme pain that you can't control at home
  • Canker sores that keep returning
  • Sores on the lips
  • Fever

Your dentist can recommend additional treatments, such as oral medications and prescription rinses.

Oral Medications

Prescription medication may be necessary for treating serious canker sores that have gotten infected.

Your dentist may prescribe tetracycline suspension (liquid) and advise you to hold the medicine in the mouth for two to five minutes before swallowing it. 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.


In rare cases, your dentist could also prescribe corticosteroids like prednisone and dexamethasone. Dexamethasone suspension (liquid) may be prescribed for use as an oral rinse with instruction to fully spit out after a certain amount of time.


Over-the-counter remedies may also help heal canker sores. But if you have one that lasts for two weeks, seems to be getting worse, or is accompanied by other symptoms like fever, see your dentist. You may need a prescription.

Was this page helpful?
Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Cleveland Clinic Foundation. Canker sores. Reviewed August 29, 2019.

  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. Huynh NC-N, Everts V, Leethanakul C, Pavasant P, Ampornaramveth RS. Rinsing with saline promotes human gingival fibroblast wound healing in vitroPLoS One. 2016;11(7). doi:10.1371/journal.pone.0159843

  4. 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

  5. El-Haddad SA, Asiri FY, Al-Qahtani HH, Al-Ghmias AS. Efficacy of honey in comparison to topical corticosteroid for treatment of recurrent minor aphthous ulceration: A randomized, blind, controlled, parallel, double-center clinical trial. Quintessenz Int. 2014;45(8):691-701. doi: 10.3290/j.qi.a32241

  6. Ramos-e-Silva M, Ferreira AF, Bibas R, Carneiro S. Clinical evaluation of fluid extract of Chamomilla recutita for oral aphthaeJ Drugs Dermatol. 2006;5(7):612-617. PMID:16865865

  7. Ediriweera ERHSS, Premarathna NYS. Medicinal and cosmetic uses of bee′s honey - A reviewAyu. 2012;33(2):178. doi:10.4103/0974-8520.105233

  8. Shilling M, Matt L, Rubin E, et al. Antimicrobial effects of virgin coconut oil and its medium-chain fatty acids on clostridium difficileJournal of Medicinal Food. 2013;16(12):1079-1085. doi:10.1089/jmf.2012.0303

  9. Rafieian N, Abdolsamadi H, Moghadamnia A, et al. Efficacy of alum for treatment of recurrent aphthous stomatitisCaspian J Intern Med. 2016;7(3):201-205. PMID:27757206

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

Additional Reading