Canker Sores

 1 Definition of Canker Sores
 2 What Causes Canker Sores
 3 Signs And Symptoms of Canker Sores
 4 Dangers And Health Risks of Canker Sores
 5 How To Prevent Canker Sores
 6 Treatments for Canker Sores
     i.  Conventional Treatment for Canker Sores
     ii. Home Remedies for Canker Sores
 7 Your Questions About Canker Sores Answered
 8 References

Definition of Canker Sores

What does a canker sore look like?

What are canker sores? Also called aphthous ulcers, canker sores are round or oval sores that occur in the mouth, usually inside the lip, cheeks, floor of the mouth or on the tongue. They may appear white or red, raw and very tender.

Canker sores are different from cold sores as cold sores are due to a virus, and canker sores may be due to irritation, stress or other underlying reasons. Approximately one out of 10 people have recurrent aphthous ulcers, or canker sores.[1]

What Causes Canker Sores

Canker sores can have numerous causes, but are most commonly due to:
  • Trauma or irritation
  • Stress and anxiety (2)
  • Dietary reasons
  • Underlying systemic health issues

They are different than cold sores, as canker sores are not caused due to the herpes virus. There may be serious underlying health problems that can cause you to develop frequent canker sores. See “Dangers and Health Risks” for information about underlying health problems that may cause canker sores. Learn more about periodontal disease causes and 100% pure liquid toothpaste at Trusted Health Products.  

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Signs And Symptoms of Canker Sores


Canker sores are usually smaller than cold sores, only taking up about three to six millimeters of space. They are round or oval with a red or raw appearance. If you have multiple canker sores or canker sores in the throat, it is most likely due to a virus such as the strain that causes cold sores.

Most aphthous ulcers or canker sores are tender and typically last 10 to 14 days. Canker sores on the tongue, canker sores in your mouth, under the tongue, or on the lips are all normal locations. Concerns arise when the canker sores or aphthous ulcers are frequent, recurring or chronic. 

Dangers And Health Risks of Canker Sores

If you have chronic canker sores that recur on a frequent basis, you should know that canker sores or other forms of oral blisters, cold sores or ulcers are a symptom of underlying health problems such as:
  • Gluten intolerance
  • Celiac disease (3)
  • Crohn’s disease
  • Irritable Bowel Disease
  • HIV
  • Nutritional deficiency
  • Leukemia
  • Behcet’s Syndrome
  • Drug induced (Fosamax, beta-blockers, NSAIDS)

If you have a condition such as gluten intolerance, your canker sores may be a natural warning to alert you to alter your diet.  

How To Prevent Canker Sores

Preventing canker sores is important for people who have problems with developing aphthous ulcers on a frequent basis. The best way to manage and limit your canker sore outbreaks include:

  • Addressing nutritional deficiencies (iron, vitamin B, folate). Here are some more things to know about oral health nutrition.
  • Using an antimicrobial mouth rinse such as one that contains essential oil to manage bacteria in the mouth
  • Addressing dietary needs such as avoiding gluten
  • Managing stress and anxiety
  • Improving your immune system through diet, exercise and adequate rest 

Treatments for Canker Sores

Most dental and medical professionals recommend treating canker sores by simply allowing them to heal on their own. If canker sores are frequent and happen more than normal, you will want to get rid of canker sores fast. In severe cases, dentists may prescribe mouthwash for canker sores or lysine for you to have on hand for another outbreak.
Alternative in-office canker sore treatment may also include:
  • Laser therapy (4)
  • Mucosal bandage
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Most remedies for canker sores are those that you can use on your own. To get rid of canker sores and limit discomfort you can:
  • Avoid trigger foods (gluten, citrus).
  • Use an antimicrobial rinse, such as one that contains an essential oil.
  • Apply healing essential oils to the area using a cotton swab. (5)
  • Apply Aloe Vera gel to the wound. (6)
  • Rinse with a solution containing milk of magnesia and liquid antihistamine for topical pain relief. Do not swallow.
  • Dab the ulcer with a cotton swab soaked in one part hydrogen peroxide and one part water.
  • Rinse with salt water solution and cover canker sore with baking soda.

Your Questions About Canker Sores Answered

How do you get canker sores? Canker sores can be caused by various triggers such as irritation or trauma to the area, food allergies, nutritional deficiencies, stress or anxiety.

Are canker sores contagious? Actual canker sores are not contagious. However, cold sores, which are viral in nature, can spread the virus through saliva - such as when sharing food or kissing.

Are canker sores herpes? Canker sores are not herpetic in nature, but cold sores are from a strain of the herpes virus. Before you become alarmed, the herpes virus also causes chickenpox and shingles. It is a different strain than that often associated with the STD.

How long do canker sores last? Most canker sores heal within 10 to 14 days. Sores that last longer than this should be examined by a professional to make sure it’s not something serious.

Why do I keep getting canker sores? Some recurrent sores may be due to underlying systemic conditions like food sensitivities (gluten or acidic foods) or triggered by stress and anxiety.

What’s the difference between cold sores and canker sores? Cold sores are viral in nature, and usually triggered by illness, stress or sunlight. The virus exists in the body and cold sores can only appear in people who have the virus. Canker sores on the other hand are usually from an irritant, stress or dietary reason and are not caused by a virus.

Is it a good idea to put salt on canker sores? No. Putting salt on a canker sore will simply cause the area to become irritated and painful. Stop gum problems before they start – Use 100% pure botanical oils to destroy harmful bacteria – Click Here to learn more.


    1. Zadik Y, Levin L, Shmuly T, Sandler V, Tarrasch RRecurrent Aphthous Stomatitis: Stress, Trait Anger And Anxiety Of Patients.; J Calif Dent Assoc. 2012 Nov;40(11):879-83.
    2. Ferraz EG, Campos Ede J, Sarmento VA, Silva LRThe Oral Manifestations Of Celiac Disease: Information For The Pediatric Dentist.; Pediatr Dent. 2012 Nov-Dec;34(7):485-8.
    3. Zand N, Fateh M, Ataie-Fashtami L, Djavid GE, Fatemi SM, Shirkavand A.; Promoting Wound Healing In Minor Recurrent Aphthous Stomatitis By Non-Thermal, Non-Ablative CO(2) Laser Therapy: A Pilot Study.; Photomed Laser Surg. 2012 Dec;30(12):719-23. doi: 10.1089/pho.2012.3301. Epub 2012 Oct 31.
    4. Altaei DT.; Topical Lavender Oil For The Treatment Of Recurrent Aphthous Ulceration.; Am J Dent. 2012 Feb;25:39-43.
    5. Babaee N, Zabihi E, Mohseni S, Moghadamnia AA.; Evaluation Of The Therapeutic Effects Of Aloe Vera Gel On Minor Recurrent Aphthous Stomatitis.; Dent Res J (Isfahan). 2012 Jul;9(4):381-5.
    6. 1Altenburg A, Micheli CK, Maldini C, Mahr A, Puttkammer M, Zouboulis CC.; [Clinical Aspects And Treatment Of Recurrent Aphthous Ulcers ↩

Article Written By Sharon Boyd

Sharon has been a Registered Dental Hygienist since 2001. She also holds a Bachelor of Science degree in Human Relations and Business. In 2011, she began implementing her dental knowledge into freelance writing services that aided dentists, product designers, continuing education providers and web marketing firms for their online and distribution purposes. She has since bridged her services into the medical and cosmetic surgery fields.

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Article Reviewed By Dr. Lara Coseo

Lara T. Coseo, DDS, is a 2004 graduate of Baylor College of Dentistry.  She has 13 years of experience practicing general dentistry.  She currently serves as a part-time faculty instructor at Texas A&M College of Dentistry and writes dental website content and blog material. Website / LinkedIn 



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