OTC treatments for canker sores.

Where to
look for
canker sores.

Link to aphthous ulcer graphic.

Off-the-shelf canker sore preparations.

While there's no real cure for canker sores (more formally, recurrent minor aphthous ulcers), there are a number of different treatment approaches that can be useful in providing palliative care (e.g. promote healing, relieve pain, prevent secondary infection).

This page explains the use of over-the-counter (OTC) treatments. These are the kinds of products you buy directly off the shelf of your local store. And their use would be most appropriate for people who just experience occasional outbreaks, involving relatively routine sized lesions.

[As alternative treatment approaches, we have additional pages that describe the use of home remedy solutions and prescription medications.]

How over-the-counter products work.

OTC medications typically provide their benefit via one, or some combination, of the following approaches:



OTC canker sore treatments -

A) Sodium lauryl sulfate (SLS) free products.


The formulation of the vast majority of mouthwash and toothpaste products contain the foaming agent sodium lauryl sulfate ("SLS").

Some studies suggest that this compound is a risk factor for, or has an aggravating effect upon, canker sores.

Animation showing locations in the mouth where aphthous ulcers typically form.

Locations where canker sores form.

SLS-free products.

A few manufacturers formulate versions of their products that don't contain SLS. It's easy enough to find them. They're usually prominently marked "SLS-free." (Related: SLS-free toothpastes.)
By using one of these alternatives, a person can reduce their level of exposure to SLS. And as a result, hopefully they'll find that they either have fewer outbreaks, or experience less intense symptoms with those sores that do form.

Of course, this treatment method can be used in conjunction with other treatment approaches or products too.

Does it work?

SLS studies haven't been entirely conclusive about what benefits can be expected. However, for any one person it should be simple enough to determine if this approach is beneficial for them.

To do so, simply keep records and compare your results with alternating periods of using and not using SLS-free products. Admittedly however, if your usual frequency of outbreaks is only occasional, this may take some time to document.

SLS-free products usually do cost a bit more than regular ones. For example, a 5 oz. tube of toothpaste might cost around 2 to 4 dollars more. So, testing to see how this approach works for you has some cost associated with it, although not a lot.

B) Barrier films / Oral bandages.

Bioadhesive paste products can create a semi-lasting film over wet oral tissues, possibly for as long as 6 hours. Two such brands are Orabase® and Zilactin®.

What the film does.

When used over canker sores, this type of covering can provide two benefits:

1) It acts as a barrier. - The film helps to protect the sore from exposure to irritating substances like foods and beverages. It also helps to create a protected environment that promotes healing.

2) It can be used as a way to apply medications. - Some manufacturers add compounds to their pastes that provide some type of treatment benefit. For example, a common addition is an anesthetic (i.e. numbing agent) whose purpose is to help to reduce levels of ulcer pain.


More modern formulations of these kinds of products are based on the compound cyanoacrylate. (This is the main component of "super" glue.) It helps to form a longer-lasting film. Orabase Soothe-N-Seal® was the first product of this type to receive FDA approval.

Does it work?

When you have a sore that hurts, none of these products probably creates a covering that's as durable as you'd like.

But yes, and especially in the case of products that contain numbing agents (discussed more below), using one can provide some relief.

The film tends to be more adherent if you dry the sore and surrounding tissue somewhat first. (A cotton swab can be used.)

Section references - Dunlap, Narang

C) Numbing agents.

Comparatively larger, or especially awkwardly located, canker sores can be so sensitive to touch that a person must limit their mouth movements (eating, chewing gum, sometimes even just smiling).

In these cases, applying a medication that contains a numbing agent to the sore may make it possible for the person to return to somewhat normal activities.

What's available?

You should be able to find products that contain compounds such as benzocaine, benzoin tincture, lidocaine, camphor, and phenol. (Benzocaine is the anesthetic compound that a dentist might rub on your gums before giving you a shot. Lidocaine is the anesthetic that's usually given as a dental shot to numb teeth.)

  • The products you find might be a liquid, gel, ointment, rinse, lozenge or spray. Or as mentioned above, some anesthetic compounds are mixed in with barrier-film pastes.
  • Some of the brand names you're likely to find are: Orabase®, Orajel®, Kank-A®, SensoGard®, Tanac®, UlcerEase®, Zilactin® and Anbesol®.


Does it work?

Numbing agents don't speed up the healing process but yes, if you're having a lot of pain they can provide some much-needed relief.

Make sure you read the instructions that come with the one you choose and follow them. Many are intended for short-term use only. If over-applied, some may cause a chemical burn.

Section references - Altenburg

D) Antibacterial compounds.


Some OTC products contain antibacterial compounds such as iodine. They may either be a liquid or paste that you apply directly to the sore. The idea is that their use helps to prevent the formation of secondary bacterial infection, which would delay the healing of the lesion.

(Ora5® contains iodine and copper sulfate. The latter is an astringent that helps to reduce ulcer pain. One study reported that the use of Ora-5® did decrease ulcer size and pain (initially). But duration still exceeded 7 days and pain actually increased between days 5 and 8.) (Dale)


Toothpaste or mouthwash that contains the antibacterial triclosan is another treatment approach that's had success with canker sores. As added benefits, this compound also has analgesic (pain-relieving) and anti-inflammatory (stifles the inflammation process, thus lesion size) properties. (Altenburg)

While studies investigating triclosan toothpaste have shown it to be safe, its use in many products has been discontinued. Colgate seems to have reformulated its Total® toothpaste so it is no longer included.

Section references - Dale, Altenburg


Some research suggests that rinsing with prescription antibacterial solutions can both speed up healing and lessen pain.

Listerine® (or a generic equivalent) can be used as an OTC substitute (two to three times a day). It does contain alcohol, however, which some people may find irritates their sores.

E) Cleansing agents.

Debris that accumulates on the ulcerated surface of a canker sore may interfere with its normal healing. Using an OTC cleansing agent can be a gentle way of removing it.

These types of products usually contain an active ingredient (carbamide peroxide, hydrogen peroxide or sodium perborate monohydrate) and glycerin (which makes their consistency syrupy).

When they're applied, they release oxygen. This, in turn, creates a foaming action that helps to cleanse the lesion and carry away debris. The release of oxygen also creates an environment that's inhospitable to some types of bacteria. The glycerin component forms a coating that helps to protect the sore. Some of the brand names associated with these kinds of products are Gly-oxide®, Amosan® and Cankaid®.

When applying these products ...

Some OTC products create a stinging sensation when they are initially applied and then, usually within some moments, start to provide relief. You may be able to minimize their initial sting by numbing your sore with an ice cube first.


 Page references sources: 

Altenburg A, et al. Practical aspects of management of recurrent aphthous stomatitis.

Dale RA, et al. The use of Ora-5 on recurrent aphthous ulcers.

Dunlap CL, et al. A guide to common oral lesions.

Narang U. Cyanoacrylate medical adhesives--a new era Colgate Orabase Soothe.N.Seal Liquid Protectant for canker sore relief.

All reference sources for topic Dental Crowns.