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Help! I Have the Worst Canker Sore Ever

Brandon practices as a community pharmacist in MN. He started as a pharmacy tech in 2003 and received his PharmD in 2011 from the U of M.


A Common Pharmacy Occurence

A 28-year-old woman comes to the pharmacy looking for some relief from her frequent, painful canker sores. She gets them at least once a month, and they show up on her tongue, lower lip, and the inside of her cheeks. Each time, they last about a week and lead to trouble eating and mild-to-moderate pain. She asks, "What can I do to stop the pain, and is there any way to avoid them in the first place?"

The short answer

Canker sores are not dangerous, and they require no treatment for them to heal. However, the pain can certainly interfere with life. Fortunately, there are ways to help alleviate symptoms.

The best way to treat canker sore symptoms is to use numbing medicine; i.e., those that have benzocaine 20% in them. There are a variety of products in different forms, and they all work similarly. Cough drops can help numb the mouth, too.

The best way to prevent canker sores is to avoid things that cause them. Common triggers include stress, acidic foods, sugary foods, and minor cuts or scrapes in the mouth (such as from biting your cheek).

Another strategy is to use a rinse (such as a 1:1 ratio of hydrogen peroxide and water) once to twice daily either continuously, or as soon as you feel a canker sore coming on.

In severe cases, there are prescription agents that can be used, or in-clinic cauterization can be done.

The Long Answer

Canker sores are mild ulcers in the mouth or on the tongue that are caused when the tissue gets damaged, either physically (biting, cutting) or chemically (stress, acidic foods). While they can be painful, canker sores are not dangerous, and they do not require treatment for them to heal. Canker sores heal naturally in 5 to 7 days.

Unfortunately, during the healing time, canker sores can cause some very annoying problems. For many people, they are very distracting and can be embarrassing. They cause pain that can interfere with eating. Depending on their location (e.g., on the tongue) they can interfere with eating.

There are two ways to treat canker sores. The first is to use a numbing agent, and the second is to create a protective barrier. Numbing agents can numb the tongue or throat and cause taste disturbances and a weird feeling when swallowing. Both tactics wear off in 30 minutes to 1 hour and need to be reapplied throughout the day.

Numbing agents come in various forms, the strongest being benzocaine 20%. It is available as a liquid, gel, paste, and pad. As they all provide the same relief, the difference is really in how you want to apply it. Liquids get all over but are easy to drizzle (like honey). Gels require more dexterity to get in place but are better for sores on the tongue.

Barriers can be formed with some products, and they are often combined with a numbing agent. You can physically see a film appear that wards of food, drink, or your own tongue.


I can't eat.

Use a benzocaine product that produces a barrier 5 minutes before eating.

Your tongue may get a little numb so food may taste funny. It will wear off the more you eat.

It hurts to talk.

Try a benzocaine product in gel form.

Gels are easier to keep in place while they get to work. Tongue sores are always tricky. You might try some cough drops.

I keep getting canker sores!

Avoid acidic or spicy foods. Reduce stress. Use a hydrogen peroxide rinse.

Some people are just prone to canker sores. Learn your triggers and avoid them.

Another medication that can be used to relieve the pain of canker sores is cough drops that have menthol in them. The strongest ones have menthol 10%. When used for coughing, menthol numbs the cough triggers in the throat, so it's not that different from numbing the canker sores in the mouth. The problem with cough drops is that they only work while you're sucking on them, so you would need a lot of cough drops in a day, which can lead to cavities and an upset stomach. Be careful!

As far as rinses go, the one that seems to work best is hydrogen peroxide mixed 1:1 (equal parts) with water. Use this to swish once or twice daily. It can help prevent canker sores from starting in the first place, treat the pain, and help them heal faster. Not everyone benefits from the rinse, but it's always worth a try.

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Read More From Healthproadvice

There are a lot of other home remedies, but none of them have enough support to be recommended. If you find something that works for you, just make sure it's safe, and then have at it!

Prescription products are also available but are used very rarely. These include steroid rinses (prednisolone) and barriers (Debacterol). In extreme cases, a physician can cauterize canker sores in the clinic. Any of these treatments are reserved for people with compromised immune systems, those at risk for complications, or those who are prone to canker sores and have their daily lives negatively impacted.

More About Cankersores

Remember, canker sores appear inside the mouth. If you have a sore that is on the outside of the mouth, such as on your lip, it is probably a cold sore, not a canker sore. Cold sores are different and require different treatment. Cold sores usually go away by themselves as well, but there are effective over-the-counter (OTC) and prescription treatments available.

Benzocaine and other numbing agents can be harmful in children if too much is consumed. Babies who are teething can be given benzocaine in smaller doses. Be sure that older children know not to swallow the liquid or gel. If you suspect a child has gotten into a bottle and may have overdosed, call poison control (1-800-222-1222).

Canker Sores Aren't Dangerous!

Canker sores are annoying, but they are not dangerous. You can't really do anything to make them go away faster, but you can treat the pain with numbing agents. The best thing to do is avoid them in the first place by avoiding triggers or using a rinse. If they get too bad, you can see a doctor and get prescription medication or have a treatment done.

Word of Caution

The information provided on this page is intended for general educational and informational use only. It is not specific, personalized healthcare advice for you. For healthcare advice regarding your particular situation, talk to members of your healthcare team.

This content is for informational purposes only and does not substitute for formal and individualized diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed medical professional. Do not stop or alter your current course of treatment. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

© 2013 Brandon Young


Paul on December 03, 2016:

Found out I was intolerant to wheat , no wheat no canker sores . I would get a mouth full of them every month, relief!!

Frank on May 06, 2016:

Have suffered from these all my life, tried everything. A few years ago I asked my new dentist when I happened to have one during a visit. He applied Debacterol, which essentially cauterises the sore. Instant relief and gone in a day or two. Discovery of this product has changed my life!

yanogator on October 02, 2015:

A common folk remedy for canker sores is tannic acid. The commercial product Tanac has it and benzocaine, so it's effective for numbing and healing. Since tannic acid is high in tea, brew a cup of tea and wring out the teabag, but leave it very moist, just not dripping. Hold that against the sore. It does help. If you have a nosebleed, stuffing one up the nostril will take care of that, too.

Brandon Young (author) from Minnestoa on July 28, 2014:

Thanks Will, I appreciate the info! I wasn't familiar with Rincinol. I looked into it and it seems to, among other things, create a protective barrier. A great idea!

Will C on July 02, 2014:

Rincinol by G.U.M has no known side effects, no burning, etc. and after going through the well known "remedies" for 25+ years, a dentist recommended this product 6 years ago and my battle, fears, phobia of canker sores is gone, over. You rinse for about a minute, spit out, and no more worries. Maybe a few hours later you'll rinse again, but usually once is enough and you forget you even had the sore. Best canker product by far. I've only ever seen it at Walgreens and it was held behind the counter (no prescription, just have to ask pharmacist for it - not sure why), so now I order one or two on Amazon and it lasts a couple years.

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