Kissing Sores – Mouth Ulcers after Brushing Teeth – Mum Stops Using Colgate – Blisters Disappear. If you suffer from recurrent mouth ulcers (canker sores) you may need to look more closely at the ingredients in your toothpaste – specifically Sodium Lauryl Sulphate is a cheap detergent many manufacturers add to make their toothpaste ‘froth’ in your mouth. More details below….
I recently popped up to the North of England to celebrate my Mother’s birthday and over cake we got on to talking about health issues. She told me that she had recently stopped using her favourite toothpaste (Colgate) because she had read that it can cause mouth sores.
She had suffered from recurring mouth ulcers for many years and had never thought it might be related to the toothpaste she had used all her life. Then she discovered that an ingredient in Colgate toothpaste called Sodium Lauryl Sulphate (SLS) can lead to something called Recurrent Aphthous Ulcers also known as Canker Sores or Mouth Ulcers.
My mother changed her toothpaste to one that was sodium lauryl sulphate free and she no longer suffers from recurring mouth ulcers.
As I have also been a life-long user of Colgate (recommended by Mum!) I decided to do some research and check out why manufacturers use sodium lauryl sulphate. I was rather disappointed to discover that this ingredient does not really contribute to the hygiene of my mouth – it is added as a kind of marketing gimmick. It actually causes the toothpaste to froth up in your mouth so you think it is helping to clean up the ‘nasties’. It is this ability to cause a froth which also makes it a popular ingredient in shampoos.

So what is Sodium lauryl sulphate or SLS? It is a cheap anionic surfactant – which means it can help oily things to mix with water. In other words it is a detergent and a popular cheap ingredient in cosmetics (helps remove oil from your skin) and as a household cleansing agent (for greasy kitchen floors). This is the stuff that Colgate-Palmolive (and other makers of SLS containing toothpaste) recommend you put into your mouth at least twice a day.
As well as creating the frothy feel when you clean your teeth SLS can also strip away the natural protective lining of your mouth. Your body’s surface cells secrete oily substances to protect the mouth and other surfaces from bacteria – these oily secretions contain natural chemicals which can attack harmful microbes. These protective substances are washed away by the detergent action of SLS (in the froth) – it also attacks the protective cells lining the surface of the mouth. This opens the door to bugs and ulcers.

Like my mother I will now be looking to replace Colgate as my preferred toothpaste with an SLS-free alternative. Manufacturers have a number of tricks to hide unwanted chemicals when listing ingredients on their packaging. For example sodium lauryl sulphate (SLS) can also be described using a number of other names like those below:
- A13-00356
- Akyposal SDS
- Aquarex Methyl
- Dodecyl sodium sulphate
- Lauryl sodium sulphate
- Monododecyl ester
- Monododecyl ester sodium salt sulphuric acid
- Sodium dodecyl sulphate
- Sodium laurylsulphate
- Sulphuric acid monododecyl ester sodium salt
(note: in the US the ‘ph’ in sulpher/sulphate/sulphuric is replaced with an ‘f’)
As a postscript I should also mention that there are other causes of sores in a person’s mouth. For example, it is possible to contract Herpes virus sores by oral sex (and other close contact with a carrier’s bodily fluids). However it is quite possible that brushing with an SLS containing toothpaste may reduce you mouth’s natural protective barriers to such infectious agents. Therefore I recommend you check with your medical adviser whether it is appropriate to use an SLS containing toothpaste prior to oral sex.

Health tip of the week: The froth in your mouth is not necessarily good for oral hygiene.
Safe brushing!
Chris Duggleby
The Author is not professionally qualified to give medical advice – if you have any concerns about sores, toothpaste or oral sex please consult your dentist or doctor.
You can read more about SLS and mouth ulcers from the US National Library of Medicine/National Institutes of Health using the articles here and here.
If you are interested in reading my other health focused articles try the following
Torture In The Shower – Face and Body Soap Allergies – Main Suspect: Pears Transparent Soap
Toxic Chemicals in Sex Toys – 18 Vibrators, Cock Rings, Love Balls Tested – Only 3 Get All Clear
My T-shirt Made Me Sick – Textile Allergies – Sinusitis From Your Underwear