canker sores 300x217 How does Sodium Lauryl Sulfate (SLS) lead to canker sores?

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What are Canker sores?

Canker sores are also known as aphthous ulcer. Patients will normally face symptoms such as soreness, burning, or prickling sensation 1 to 2 days before the appearance of the ulcers.

Normal surrounding of your mouth will appear normal or there will be some red macules at the future sites of the ulcers. There are three recognisable type of aphthous  ulcers , minor aphthous ulcers, major aphthous ulcers, and  herpetiform ulcers.

They are grouped according to the diameters of the lesions.

i) Minor aphthous ulcer –

which is the commonest type of canker sores,  you will have one to five ulcers which are normally round/ oval in shape and have diameters of less than 10 mm. You will  feel very painful and the ulcers will heal in a week’s time without leaving a scar and will reoccur within 1 to 4 months time.

ii) Major aphthous ulcers:

They are larger in size , more than 10 mm in diameter. occurs  anywhere in the mouth, and mostly develop after puberty . They appeared from one to ten in numbers and heal in 4 to 6 weeks time with scarring.

iii) Herpetiform ulcers :

They are small, pin head size ulcers , 1 to 3mm and they might appear in large numbers , or in a cluster form. This type of ulcers will heal within 2 to 3 weeks, and will recur at less than a month. This is mostly occurs in older age group.

Aetiology is unknown, but factors below are believed to contribute in causing canker sores.

i)                    Hereditary predisposition

ii)                   Trauma

iii)                 Emotional stress

iv)                 Microorganisms or infective agents

v)                  Allergic disorders etc food particles

vi)                 Haematological disorders

vii)               Gastrointestinal disease

viii)              Hormonal Disturbance

Is my  toothpaste giving me canker sores? What is SLS actually?

SLS stands for Sodium Lauryl Sulfate and is an ester of Sulphuric acid. Sodium Lauryl Sulfate (SLS) is an anionic surface which is found in products such as detergents, toothpastes , shampoos soaps which are used to create foams and is used as surfactant to remove stains and residues. It is widely used in products due to its effectiveness as foaming agent. Another closely related variant of Sodium Lauryl Sulfate(SLS) is Sodium Laureth Sulfate which is less irritating but give a long lasting effect to the human body. It has been proven in a lot of studies that Sodium Lauryl Sulfate (SLS) causes primary irritation to our skin. It has degenerative effect on cell membranes because of its protein denaturing properties , thus along with this and immune system of the body leads to formation of canker sores.

So what can we do?

There are studies which  found out that there is significant reduction in number of canker sores by changing to SLS ( Sodium Lauryl Sulfate)  free dentifrice.

There are quite a number of SLS free toothpastes available in pharmacies or drug stores that you can purchase, for example, Biotene Antibacterial Dry Mouth Toothpaste, Squigle® Enamel Saver® Toothpaste, The natural Dentist Toothpaste.

Here are some tips on how to manage canker sores.

  1. Gargle salt water.  Add one tbsp with warm water, and  gargle it few times a day.  Salt can draw water from pathogens, and it’s effective in killing bacteria and germs.

Another alternative for mouth wash is to add baking soda with salt water.

  1. Place H202 on the spot of canker sore, make sure u dilute it with water. ( 1 part  Hydrogen peroxide to 1 part of water) hydrogen peroxide can acts as antiseptic, and cause soothing effect.
  2. Rinse mouth with milk of magnesia.
  3. Consume diet which are rich with vitamin B12 such as cereals , milk products which promotes tissue healing.
  4. Alternatively you can dissolve vitamin B12 under your tongue.
  5. Juices such as plum juice, aloe Vera juice are to promote healing of the ulcers.
  6. Use a softer toothbrush to clean your oral cavity.
  7. Prevent consuming spicy food.
  8. Go for professional consultation. Dentists will normally prescribe medications such as corticosteroids for canker sores.


  1. Carolynne
    Posted December 18, 2011 at 10:34 pm | Permalink

    There is an incorrect statement here. Tom’s of Main toothpaste is listed as one that does not contain SLS, when it actually does contain Sodium Lauryl Sulfate. Very disapointed.

  2. SH
    Posted December 19, 2011 at 1:21 am | Permalink

    thanks for the information and sorry for the mistake!!

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