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Canker Sore Home Treatments

Canker sores, also known as aphthous ulcers, are painful sores that can develop on the cheeks, gums, tongue, and lips. While canker sores are not contagious and will typically go away on their own, they are painful, making it difficult to talk and eat. For this reason, many people look for home remedies to reduce pain and discomfort.

What are Canker Sores?

Canker sores are more common in people with some inflammatory and immune-mediated diseases, but they also occur in the absence of any systemic disease.1

Typically, canker sores are smaller than one centimeter in diameter, with two to four ulcers clustered together. These round, painful ulcers heal without scarring.

Canker sores are the most common type of mouth lesion in healthy people. Recurrent canker sores are most common in young adults and adolescents. These lesions can recur several times a year, with each flare lasting up to two weeks.

Other causes of mouth ulcerations and pain include:1,2

  • Trauma
  • Drug-induced ulcers
  • Immune-mediated conditions
  • Anemia
  • Cyclic neutropenia (low white blood cells)
  • Nutritional deficiencies
  • Viruses: Coxsackie A, herpes simplex, herpes zoster, cytomegalovirus, Epstein-Barr, syphilis, and human immunodeficiency virus (HIV)
  • Bacterial infections
  • Behcet syndrome

If you have a white patch in your mouth, not an ulceration, see a doctor or dentist for evaluation. Cancers, fungal infections, and autoimmune conditions can cause these white lesions.

A person with an aphthous ulcer

Causes of Canker Sores

Canker sores are not contagious. The exact cause of canker sores is not known. However, they are not caused by the herpes virus (cold sores). Potential causes or triggers of canker sores include:2,3,4,5,6

  • Local mouth trauma: dental appliances, biting the inside of the mouth, teeth injuries, poorly fitting dentures, and orthodontics can irritate the lining of the mouth.
  • Genetic predisposition: a predisposition for canker sores is more common in some families.
  • Nutritional deficiencies: vitamin B12, folic acid, zinc, and iron deficiency may be associated with canker sores.
  • Infections: some viruses and bacteria have been linked to the development of canker sores.
  • Irritation from foods or chemicals: spicy or acidic foods, food allergies, food preservatives, smokeless chewing tobacco, and sodium lauryl sulfate, a common ingredient in toothpaste, is associated with developing canker sores.
  • Allergic reactions: allergies to certain foods, mouth bacteria, or nickel can trigger canker sores. Over-the-counter allergy medications can help reduce symptoms.
  • Stress: Emotional stress is thought to trigger canker sores.
  • Hormones: fluctuations in hormone levels during menstruation, pregnancy, and menopause may trigger canker sores.
  • Immune-mediated conditions: inflammatory bowel disease and Behcet’s disease include canker sores as a common symptom.

Signs and Symptoms of Canker Sores

Canker sores are red and white, shallow ulcers in the mouth. They are localized, round to oval, and have a yellowish center and a red border. Canker sores should heal within 14 days. See your doctor or dentist if you have a fever, swollen lymph nodes, or extreme fatigue.

Salt water rinse

Home Canker Sore Treatments

Since canker sores are not contagious and significantly compromise quality of life, it makes sense to try home remedies that could decrease pain and speed up healing.

Try some of these home remedies.  

Saltwater rinses

Mix one teaspoonful of salt in one-half cup of water. Mix well. Swish salt water around in your mouth and gargle with it. Spit it out once you’re done. You may notice a slight stinging sensation at first.

Saltwater can help reduce bacteria in your mouth and neutralize acidity. Never put salt directly on a canker sore. It will sting and could further damage irritated mouth tissue.

Baking soda rinses

Baking soda neutralizes acidity in the mouth and reduces canker sore pain. Mix one teaspoonful of baking soda in one-half cup of warm water. Swish the baking soda mixture around your mouth for 20 to 30 seconds, then spit it out. Repeat several times per day.


Honey has antimicrobial and anti-inflammatory properties. Dry your aphthous ulcer and apply honey several times per day to reduce pain and redness.

Coconut oil

Coconut oil may have antimicrobial and anti-inflammatory properties. Dry your aphthous ulcer with a Q-Tip. Then apply coconut oil to create a protective barrier over the ulcer.6

Hydrogen peroxide

Some over-the-counter products have hydrogen peroxide in them to reduce bacteria and inflammation. Dilute a 3% solution of hydrogen peroxide with equal parts of water. Dip a Q-Tip into the solution and apply it to your aphthous ulcer several times each day.


Sucking on ice chips may numb aphthous ulcers and improve pain.

Milk of magnesia

Mix a teaspoonful of Milk of Magnesia with one teaspoonful of diphenhydramine (Benadryl). Swish the mixture throughout your mouth for a minute, then spit it out. Benedryl is an over-the-counter medication used to treat allergies.

Alum powder

Alum powder has astringent and anti-inflammatory properties. Create a paste using a small amount of alum powder and a drop of water. Apply the paste to your canker sore and leave it in place for a minute or so. Rinse your mouth thoroughly after use.

In one study, using alum-impregnated patches decreases aphthous ulcer time by five days.7

Over-the-counter products

Rinse your mouth out with alcohol-free mouthwashes. By decreasing bacteria in the mouth, mouthwashes may speed up healing.

Over-the-counter creams, gels, and liquids have active ingredients that numb canker sores. Look for products that contain benzocaine.

In addition to locally acting medications, local anesthetics, prescription corticosteroids, and non-steroidal anti-inflammatory drugs (NSAIDs) can reduce pain and inflammation.

Check with your doctor before using these over-the-counter products. Ask your doctor or pharmacist which option is most likely to be effective for you before mixing medications.

A woman talking to a telehealth doctor

When to Seek Medical Help?

If your canker sore persists or recurs, or if you develop signs of infection, such as fever and swollen glands, contact your doctor. If your aphthous ulcer is large, has significant redness, your pain worsens, or you are unable to stay hydrated, you may require prescription medications.

Finding an online doctor is easy using the Telegra MD platform. A doctor on call is available 24 hours a day to help when needed. Your online doctor can provide an online diagnosis, differentiate between a cold sore and a canker sore, and transmit an online prescription to a local pharmacy if appropriate. You will likely find that a telehealth appointment is much more cost-effective than an in-person appointment.


While we strive to always provide accurate, current, and safe advice in all of our articles and guides, it’s important to stress that they are no substitute for medical advice from a doctor or healthcare provider. You should always consult a practicing professional who can diagnose your specific case. The content we’ve included in this guide is merely meant to be informational and does not constitute medical advice.


1. Lodi, G. Oral Lesions. UptoDate. Updated July 2023. Accessed August 13, 2023. Oral lesions – UpToDate

2. Edgar NR, Saleh D, Miller RA. Recurrent Aphthous Stomatitis: A Review. J Clin Aesthet Dermatol. 2017 Mar;10(3):26-36. Epub 2017 Mar 1. PMID: 28360966; PMCID: PMC5367879.

3. Canker sore. (n.d.). Medlineplus.Gov. Retrieved August 13, 2023, from

4. Keenan AV, Spivakovksy S. Stress associated with onset of recurrent aphthous stomatitis. Evid Based Dent. 2013 Mar;14(1):25. doi: 10.1038/sj.ebd.6400919. PMID: 23579306.

5. Kounoupis V, Andreadis D, Georgaki M, Albanidou-Farmaki E, Daniilidis M, Markopoulos A, Karyotis N, Nikitakis NG, Poulopoulos A. IL-10 and TGF-β1 gene polymorphisms in Greek patients with recurrent aphthous stomatitis. Med Oral Patol Oral Cir Bucal. 2022 Sep 1;27(5):e426-e433. doi: 10.4317/medoral.25352. PMID: 35660731; PMCID: PMC9445602.

6. Chiang CP, Yu-Fong Chang J, Wang YP, Wu YH, Wu YC, Sun A. Recurrent aphthous stomatitis – Etiology, serum autoantibodies, anemia, hematinic deficiencies, and management. J Formos Med Assoc. 2019 Sep;118(9):1279-1289. doi: 10.1016/j.jfma.2018.10.023. Epub 2018 Nov 14. PMID: 30446298.

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

8. Rafieian N, Abdolsamadi H, Moghadamnia A, Jazayeri M, Seif-Rabiee M, Salmanzadeh M, Radi S. Efficacy of alum for treatment of recurrent aphthous stomatitis. Caspian J Intern Med. 2016 Summer;7(3):201-205. PMID: 27757206; PMCID: PMC5062179.

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