Canker Sores

Frequently Asked Questions

• How do you get rid of a canker sore?

  Most canker sores heal on their own within one to two weeks without treatment. To ease discomfort in the meantime, you can rinse with a saltwater or baking soda solution, apply an over-the-counter numbing gel containing benzocaine, or use an adhesive patch designed to protect the sore from irritation. A Rexall Pharmacist can assess your symptoms and recommend or prescribe a treatment if your sore is particularly painful or slow to heal.

• How do you get rid of a canker sore in 24 hours?

  There is no guaranteed way to eliminate a canker sore within 24 hours, but acting quickly can reduce pain and speed healing. Applying a numbing gel or an over-the-counter adhesive patch as soon as the sore appears can help protect the tissue and reduce irritation. Rinsing with a saltwater solution and avoiding acidic or spicy foods may also limit inflammation. For persistent or severe sores, speak to your Rexall Pharmacist for prescription treatment, if appropriate following an assessment.

• What causes canker sores?

  The exact cause of canker sores isn’t fully understood, but several factors are known to trigger them. These include stress, minor mouth injuries (such as biting your cheek or irritation from dental work), nutritional deficiencies in iron, folic acid, or vitamin B-12, and certain acidic or spicy foods. Some people have a genetic predisposition, and canker sores may also be associated with immune system responses or an overreaction to oral bacteria.

• What is a canker sore?

  A canker sore, also known as an aphthous ulcer, is a small, shallow lesion that develops on the soft tissues inside the mouth — typically on the inner cheeks, inside of the lips, or on the tongue. Unlike cold sores, canker sores are not caused by a virus and are not contagious. They can be painful and may make eating or speaking uncomfortable, but most resolve on their own within one to two weeks.

• What does a canker sore look like?

  Canker sores typically appear as a round or oval white or yellowish spot surrounded by a red, inflamed border. They form on the soft tissues inside the mouth, such as the inner cheeks, lips, tongue, or the base of the gums. You may notice a tingling or burning sensation in the area one to two days before the sore becomes visible. Most canker sores are small (under 1 cm), though larger or more numerous sores can occasionally occur.

• What is the white stuff in a canker sore?

  The white or yellowish material in a canker sore is a fibrinous membrane — a layer of protein and immune cells that forms over the ulcer as part of the body’s natural healing response. This protective coating helps shield the exposed tissue from bacteria and further irritation. It is not pus, and attempting to remove it can delay healing and increase discomfort.

• Is a canker sore herpes?

  No. Canker sores are not caused by the herpes virus and are not contagious. They are aphthous ulcers that form inside the mouth due to triggers such as stress, injury, or nutritional deficiencies. Cold sores, on the other hand, are caused by the herpes simplex virus and appear on the outside of the mouth, most often on or around the lips. If you’re unsure whether you have a canker sore or a cold sore, a Rexall Pharmacist can help you tell the difference.

• How do you heal a canker sore fast?

  To speed up healing, start by rinsing your mouth with warm saltwater or a baking soda solution several times a day to reduce bacteria and inflammation. Applying an over-the-counter numbing gel or an adhesive patch can protect the sore and reduce pain. Avoid spicy, acidic, or rough-textured foods that can irritate the tissue. For faster relief, your Rexall Pharmacist can assess your sore and write prescription treatment, if appropriate.

• Can you pop a canker sore?

  No — you should not try to pop or burst a canker sore. Unlike a pimple or blister, a canker sore is an open ulcer, not a fluid-filled lesion, so there is nothing to pop. Attempting to do so can introduce bacteria, worsen the wound, increase pain, and delay healing. The best approach is to leave the sore alone and use gentle treatments like saltwater rinses or protective gels to ease discomfort while it heals naturally.

• Can a Rexall Pharmacist help with canker sores?

  Yes. In most Canadian provinces, a Rexall Pharmacist is authorized to assess canker sores as a minor ailment and recommend or prescribe appropriate treatment. They can suggest over-the-counter products such as numbing gels, protective patches, or antimicrobial rinses, and may write a prescription for more stubborn sores. If your symptoms suggest a more serious underlying condition, your pharmacist can also refer you to a physician. Book Consultation at your local Rexall today.