Canker Sores and Bad Breath…Caused by Toothpaste?

Canker Sores (Mouth Ulcers)

Canker Sores (Mouth Ulcers)

Canker sores, also known as “mouth ulcers,” plague the lives of millions of people all over the world. These small oral ulcers can make life unbearable when eating, drinking, speaking, or swallowing. Frustration sets in when your dentist or doctor doesn’t know how to respond to your questions about these annoying and recurring ulcerations.

Unfortunately, the public ends up creating their own canker sore problem by using commercial toothpastes, which contain an ingredient that is proved to be linked to canker sores. It’s called sodium lauryl sulfate (SLS), and it is placed into toothpastes and some mouthwashes in order to create foaming! (Sodium lauryl sulfate is also the main ingredient in your shampoo – go check it out.)


What Causes Canker Sores ( Mouth Ulcers)?

The latest research shows that certain chemical compounds trigger the production of canker sores. Among those items is something that may shock unsuspecting people. It’s SOAP. Yes, but it’s soap, inside your mouth. For many years the major pharmaceutical companies have used soap (chemically known as sodium lauryl sulfate) in order to create a foaming agent when one brushes their teeth. Why? The foam does not provide any benefits to the toothpaste, but does fool the you, the user, into thinking that a foaming action is related to a “cleansing” action. After speaking to many of these pharmaceutical companies, the following excuse is used: “we use sodium lauryl sulfate as a surfactant, in order to blend all of our ingredients together and make them work more effectively.” (A surfactant is a chemical agent, which allows other chemical molecules to get closer to each other. However, there are many surfactants out there that are not soapy or do not cause allergic reactions resulting in canker sore production.

One of the most exciting advances has been the establishment of the link between canker sores and an ingredient common to almost all toothpastes. The additive SLS may be a culprit in canker sore formation.

SLS acts just like a detergent. It is used in the laboratory as a membrane destabilizer and solubilizer of proteins and lipids. SLS is used in toothpaste to emulsify (mix) oil and water based ingredients together. In your toothpaste, it creates the foam you get when brushing. Since it is classified as a soap, you will easily understand why this ingredient can cause drying inside the mouth for many individuals. The dryness is one of several factors that will lead to bad breath.

The thought is that SLS may, in susceptible individuals, cause microscopic trauma or membrane disruption to the skin cells in the mouth. This along with trauma or actions of the immune system may lead to canker sore formation.

Recent studies have shown a link between the use of toothpastes containing SLS and the occurrence of RAS (canker sores).

The Science of Canker Sores:

Canker sores are interchangeably known as: mouth ulcers, aphthous ulcers, recurrent aphthous stomatitis, or oral ulcers.

Some people (and doctors) confuse canker sores with “cold sores” (fever blisters). We know both are painful, annoying, and recurring. Here are the major differences: 


Canker Sores

Cold Sores

Only occur inside the mouth

Mostly on outside of mouth – sometimes on the inside of the mouth, but only on “hard” surfaces (palate)

Not Contagious


Not Viral (not caused by a virus)

Caused by Viruses

Caused by damage to oral tissue, often by sodium lauryl sulfate, a common foaming agent ingredient in almost all toothpastes

The first sign is appearance of small blisters (vesicles)

 The following is a synopsis of 3 European Scientific Studies:

In a study at the University of Oslo in Oslo, Norway, Drs. Barvoll and Brokstad revealed a 60-70% reduction in the number of canker sores in patients who used SLS-free toothpaste during the three month test period. Additional studies have since shown equally promising results.

In the clinical studies, patients using SLS toothpaste displayed a greater amount of desquamation (loss of a layer of skin lining the inside of the mouth). This has led to the theory that SLS may contribute to RAS (canker sores) by causing injury to the oral epithelial cells (skin cells lining the inside of the mouth).

SLS, by denaturing protective mucus proteins, may also disrupt the protective layer of mucus which lines the inside of the mouth (a denatured protein is a protein which has lost its three dimensional shape thereby becoming nonfunctional and useless). The denaturing of mucus proteins makes the cells lining the mouth more susceptible to injury and canker sore formation.


1. Herlofson, Bente and Pal Barkvoll sodium lauryl sulfate and recurrent aphthous ulcers: A preliminary study Acta Odontol Scand 1994; 52:257-259

2. Herlofson, Bente and Pal Barkvoll The effect of two toothpaste detergents on the frequency of recurrent aphthous ulcers Acta Odontol Scand 1996; 54(3): 150-153

3. Barkvoll, Pal and G. Rolla Possible effects of sodium lauryl sulfate (SLS) on the oral mucosa [abstract] J Dent Res 1989; 68:991

What is especially exciting is the fact that many of my patients have experienced tremendous improvements as a result of using SLS-free toothpaste. Additionally, many of the visitors to this website have also found canker sore relief by using an SLS-free toothpaste.

Research is being conducted to determine what makes a person susceptible to canker sores in the first place as well as what actions and mechanisms trigger canker sore outbreaks. Among those things that may trigger an attack or make a person more susceptible are:

A. SLS found in Toothpaste and some mouthwashes

B. Allergies to Food Products and Certain Preservatives

C. Trauma from Brushing your Teeth too vigorously

D. Lip Biting

E. Stress

F. Trauma from Eating Hard, Rough Foods (Potato Chips, Pretzels)

G. Deficiencies in Vitamin B12, iron, and folic acid.

Current theories on the causes of canker sores have focused on the immune system. This research suggests that canker sores may be caused by the body’s own immune system attacking the cells lining the inside of the mouth.

The first canker sores usually occur between the ages of 10 and 20. During life, episodes usually but not always become less frequent and less severe. Interestingly, women often report increased susceptibility to canker sore formation during certain times of their menstrual cycle. Some women report complete relief from canker sores during pregnancy.

Interestingly, canker sores affect people to varying degrees of severity. Some people may get an occasional outbreak of canker sores once or twice a year while others may suffer near continuous overlapping episodes of canker sores.

On the Subject of Preventing Canker Sores (Mouth Ulcers)

The most important piece of advice we can give you is to stay away from toothpaste which contains sodium lauryl sulfate (click for list).

Secondly, trauma to the inside of the mouth may trigger the production of canker sores. This trauma includes overzealous tooth brushing, biting your cheek or tongue, and scraping the inside of your mouth with hard or sharp foods (like hard pretzels).

Cut down on eating foods like potato chips, hard pretzels, cut apples, and hard candies which might nick, abrade, or otherwise traumatize the oral tissue.

As far as overzealous brushing, most people can not consciously stop brushing so hard, because toothbrushing is such an ingrained habit. Consequently, we encourage them to use our SuperSoft Nylon Toothbrush, made for us by experienced toothbrush manufacturers in England. It’s virtually impossible to cause damage with these soft, yet strong bristles.

We know that many bite the insides of their cheeks while sleeping or out of nervousness and stress. We suggest that a mouth guard be worn during sleep. This is often very effective at preventing further oral trauma. Contact your dentist for more information.

Reactions to certain food products may be responsible for many cases of canker sores. Among the foods that may cause canker sores in certain people are: nuts, peanut butter, seafood, wheat products, chocolate, and milk.

Treatment of Canker Sores

Usually canker sores clear within 7-14 days without treatment. During this time, however, the canker sores can be painful especially when people eat or drink. Treatment helps ease the pain and may help reduce the amount of time it takes for the ulcers to go away.

Other Viable Treatments:

1. Anti-Microbial Mouthwashes

Surprisingly the use of anti-microbial mouthwashes has provided effective relief for many. Canker sores are not caused by a bacteria or virus so the mechanisms by which these anti-microbial mouthwashes work remain unclear. Commonly used are anti-microbial oxygenating mouthwashes (TheraBreath Oral Rinse and PerioTherapy Oral Rinse).

2. Analgesic (Pain Relieving) and Protective Ointments and Gels:

Your local drug stores stocks some pain relieving medications, including Zilactin or Oragel. After application, they create a protective cover over the sensitive areas.

3. Corticosteroid Rinses and Gels:

These are prescription medications that must be authorized by your dentist or physician and should only be used for severe or painful cases. The application of these types of gels and rinses may be painful at first. The most common is a topical steroid gel (non-alcoholic) of lidex applied very gently to the ulcer 2-4 times per day.

Systemic Conditions Associated with Canker Sores (Mouth Ulcers)

In a very small number of cases, canker sores may be indicative of a bodily (systemic) disorder. A medical condition known as Behcet’s Disease, for instance, has amongst its symptoms: canker sores, genital lesions, eye lesions, and dermal afflictions.

Those infected with HIV may also develop “canker sore-like” ulcers.

Some digestive conditions display canker sores as part of their disorder. These include: Crohn’s Disease, Celiac Disease, Ulcerative Colitis, and gluten hypersensitivity (wheat allergy).

Consult your physician if any of the above sound like they may be part of your canker sore problem.


7 Responses to “Canker Sores and Bad Breath…Caused by Toothpaste?”

  1. crohns diet Says:

    I like this blog…excellent info. Will save it as a favorite. Do you have a facebook page?

  2. admin Says:

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  4. improve sexual stamina. Says:

    Excellent article, A well written article that i am sure took some time. I have leared some valuable information from the post. I will be searching for tooth paste with the aforementioed chemical. I rarely get canker sores but know many that do, I will share this information with them. Thank You

  5. Zubair Ahmed Says:

    Mouth ulcers are painful so say the least. I have suffered with them since an early age. No doctor has ever prescribed any medication that has occurred. Until fairly recently I started to self medicate.

    I have found by taking high dosage of Vitamin C with Zinc, AC, Selenium and Saw Palemetto has improved my condition. Now I don’t get as many ulcers and when I do they heal allot faster and are less painful.

  6. How To Get Rid Of Canker Sores In Your Mouth Says:

    It’s amazing to think that something we are doing to try to take care of our teeth and gums could actually be hurting our mouth! I think more research should go into these supposed health products before they can be marketed as beneficial.

  7. My Canker Sore Treatment Says:

    Great article on canker sores. Most people don’t realize how harsh SLS’s are. I have found several toothpastes that are SLS free, including Tom’s of Maine Clean and Gentle formula, Rembrandt C, Sensodyne Iso-Active, and Boitene.

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