Woman with a canker sore

Canker sore causes and what to do about them

Do you ever get canker sores? These unpleasant outbursts, also known as mouth ulcers, are little crater-like welts that can appear on the inner lining of the mouth, tongue or lips. Although usually harmless they aren’t too fun and can cause pain or irritation. Especially canker sores on the tongue can create great discomfort. In this article, we look at the causes of canker sores and importantly, how to relieve canker sores.

What causes canker sores?

The science behind canker sore causes is still not 100% clear. There are a few things that are thought to trigger these little outbursts, but in reality, why they come and go and when they do, changes from person to person. If you find yourself affected and are wondering ‘what causes canker sores in the mouth’, here are a few things to watch out for in daily life:

  • Particular food groups: There are a few different types of foods that may cause mouth ulcers. These include rough edged foods, chocolate, wheat, spicy or very hot foods and citric acid (as found in lemons, limes, oranges etc).
  • Mouth irritation: Think poorly fitting dentures or a defective filling that rubs against the side of the cheek. Accidentally biting your cheek can have a similar effect and can trigger canker sores on gums.
  • Certain types of toothpaste: Some toothpaste contains sodium lauryl sulphate and experts believe this could be one possible cause of canker sores.
  • Stress and anxiety: Health professionals also think stress and anxiety might play a role in causing this problem, especially if it’s reoccurring.
  • Hormonal changes: Having more or less of certain hormones can be another cause of canker sores on the tongue, mouth or lips. Women sometimes develop mouth ulcers around the time of their monthly menstruation and are more susceptible during pregnancy
  • Stopping smoking: While quitting smoking is great for your health, it can have this unfortunate side effect. If mouth ulcers are making it difficult to give up cigarettes talk to a healthcare professional for advice.
Zendium How to relieve canker sores

Health professionals also think stress and anxiety might play a role in causing mouth ulcers.

Those are some of the believed key causes of canker sores. If you think you might be at risk watch out for the symptoms: a painful sore or sores inside your mouth (on the tongue, lips, soft palate or inner cheeks).

Zendium Canker sore tongue causes

How to relieve canker sores?

Now you know what causes canker sores on the tongue or the gums, but what can help with the discomfort and pain? Check out the following tips:

  1. Switch to a mild and gentle toothpaste like Zendium Complete Protection to avoid irritating mouth ulcers further.
  2. One good way to relieve canker sores is to avoid the foods mentioned above. While possibly causing mouth ulcers, these food groups may also exacerbate them when present.
  3. Another good possible way to relieve canker sores is to clean your teeth with a soft brush and maintain good oral hygiene.
  4. Cover the ulcer in a protective paste as recommended by your pharmacist.

Hopefully after a week or so your mouth ulcers will go away on their own. However, if canker sores in your mouth do seem to reoccur often or if you have an ulcer or multiple that are very red, painful or long-lasting (over three weeks) always see a dentist or doctor for further advice. You can also check our separate article about treating canker sores to learn more, but remember that this doesn’t replace a visit to your dentist.


The advice in this article does not constitute medical advice, it is solely available for information purposes. We recommend that you consult your dentist if you are experiencing any gum or tooth problems.