To help your canker sore feel better:

  • Avoid foods that hurt—foods that are hard, crusty, sharp, spicy, salty, acidic or hard to chew. Examples are: crackers, potato chips, pickles, oranges, lemons, tomatoes and fruit juices.
  • Take care to keep your teeth and gums clean but be careful not to hurt the canker sore. Brush your teeth using a soft toothbrush twice a day and use dental floss once a day. Use a new soft toothbrush if your old one has splayed or broken bristles that can hurt your mouth or the canker sore.
  • Rinse your mouth with 1/2–1 teaspoonful (2.5–5 mL) of table salt dissolved in 1 cup of warm water several times a day to help soothe the canker sore. Use this rinse after meals to remove bits of food that may bother the canker sore. Be sure to spit out the salt water after rinsing.
  • Most mouthwashes for bad breath have a high alcohol content and using them will make the canker sore sting. Don’t use these mouthwashes when you have a canker sore.
  • A canker sore should get better on its own in 10 to 14 days. Your pharmacist may suggest you use an ointment with an anesthetic in it to help the pain for a short time. You may use this 4 times a day for no longer than 14 days. Put a small amount of anesthetic ointment on the canker sore, using a cotton-tipped swab (Q-Tip), before eating meals and before going to bed.
  • Your pharmacist may suggest that you cover the canker sore with a small amount of Orabase or Zilactin to help lessen the pain.
  • You may use a non-prescription pain medicine such as acetaminophen to help reduce the pain. Your pharmacist can help you choose a pain medicine that is right for you and tell you how to take it.

To help prevent canker sores:

  • If you sometimes bite the inside of your cheek and a canker sore appears at that spot, take extra care while chewing. Chew your food slowly and try not to talk while you are chewing.
  • If you have any teeth or dental work with sharp points, see your dentist so that the sharp points can be made less irritating.
  • Most toothpastes have an ingredient called sodium lauryl sulfate. Some people have fewer canker sores when they use a toothpaste that does not have this ingredient in it. Your pharmacist can suggest a toothpaste, if you want to try this approach.

You should see a doctor or dentist if:

  • The canker sore is still there after 14 days.
  • If the canker sore has gotten larger or if more canker sores have developed.
  • The pain is not controlled when using the medication recommended, and you have difficulty chewing or swallowing.
  • If you also feel sick, have a fever, pain in the joints, irritated eyes or many, watery bowel movements.
   Minor Ailments. © Canadian Pharmacists Association, 2013.  All rights reserved.