Skip to main content

Common Causes of Canker Sores


What are canker sores?

A canker sore is a shallow red sore (ulcer-like) in your gum, inner cheek or tongue. All canker sores have a red boundary surrounding a white or yellow center. (This is pus) If you happen to spot something that fits the above description, you should automatically know that what you’ve got right there is a canker sore.

The people who most commonly get canker sores are women, adolescents, and people between the ages of 10 to 40. As you grow older, you may notice that the canker sores appear less and may be even not anymore. For this reason, I highly think the causes of canker sores are related to hormonal changes and shifts, commonly experienced by teenagers.


The causes of canker sores are not clearly known. Although there are a variety of explanations for their occurrence, some people suggest that canker sores often run in families. Personally, I have suffered from canker sores ever since my early teens and for me – none of my family members have ever suffered from canker sores. Thus, the saying that you get canker sores because your dad or mom had them is quite faulty and clearly depends on the person.

So, we come back to the question - what are the causes of cancer sores? Here, we have listed possible causes of canker sores:

  • Injuries to the Mouth region. Wounds or cuts in the mouth, dental mishaps, hurting your mouth during sports, straying of your toothbrush into your gums while brushing, or even mistakenly jabbing your gum with a sharp object such as your nail, can cause canker sores.
  • Do you have braces? When you have braces, they can rub on your inner cheeks, lips and tongue as you talk, eat or even just swallow. The metallic part of the braces can cause small friction wounds or cuts on the sensitive skin of your mouth and this can form canker sores.
  • Allergic Reactions from Foods. Some people, who excessively feed on certain foods or eat foods that they are allergic to, may cause canker sores to form in the mouth. These foods may be chocolate, eggs, nuts, fruits with high acidic content, cheese, coffee, hard candy and many others you can only be wary of if you see a canker sore popping up after consuming them.
  • Overly consuming highly acidic foods. Have you recently had a heavy dose of oranges, pineapples or any other highly acidic foods? If yes, then that might be a possible cause of canker sores.
  • Vitamin Deficiency. One of the inborn causes of canker sores is deficiency of some nutrients in the body like folic acid, iron and vitamin B12. Eating iron rich vegetables foods, foods rich in folic acid and foods rich in cobalamin/vitamin B12.
  • Toothpastes or mouth gels. Some toothpastes and mouth washes contain ingredients like Sodium Lauryl Sulfate that may irritate your gums, lead to build up of these toxic chemicals and finally cause canker sores.
  • Emotional Stress or Anxiety. Many signs of emotional stress or anxiety show up physically on your body through hair loss, dark circles, acne, pimples and many others. Canker sores on your tongue, gum or inner cheek is also one symptoms of prolonged stress or anxiety.
  • Hormonal Changes prior to menstrual cycles.
  • HIV/AIDS. People suffering from HIV/AIDS may be prone to mouth infections and canker sores.
  • Celiac disease and Behçet's disease may also be principal and underlying causes of canker sores as they are characterized by appearance of canker sores in the mouth.
  • Inflammatory bowel diseases such as Crohn’s disease and ulcerative colitis might also be possible causes for canker sores.
  • Weak immune system. If you’re someone who absolutely avoids veggies, rarely consumes fruits and suffers from frequent colds, infections and canker sores, then you should really reconsider adjusting your diet. If you’re reading this, then I don’t think you're such a person – but I know of people with weak immune systems brought about by insufficient amounts of vitamin C in their diet.

Although it is a common myth that canker sores are symptoms of herpes and other related disease, it isn’t true. However, a possible cause for canker sores is Helicobacter pylori, which is a popularly known bacterium that is responsible for causing peptic ulcers.

Do you often get canker sores? Or is this your first time getting a canker sore? Can you think of anything you did differently that could have caused your canker sore? Please share your experience below so that others can benefit.

Scroll to Continue

All free photos in this hub are from & Wikimedia Commons. Photos edited by healthmunsta.



healthmunsta (author) on April 15, 2014:

So true! Braces can cause canker sores - I've added this to the list.

Unknown on April 15, 2014:

Another reason is braces rubbing up against your tongue and lips

healthmunsta (author) on July 05, 2013:

Hi peachpurple! I used to suffer from canker sores too. But after adopting a healthier lifestyle, I've noticed that I haven't got a canker sore at all. It definitely has a bit to do with nutritional deficiencies.

peachy from Home Sweet Home on July 04, 2013:

my whole family is prone to canker sores. They have these sores almost every month, especially if they accidentally bite their own flesh or poked by fish bones. I believe that vitamin deficiency is the main problem. Thanks for listing the rest of the possibilities. Voted up

Related Articles