Mouthwash, cosmetics, and medical devices

A recent case report published in Contact Dermatitis in August serves as a useful reminder of the grey area between cosmetic products and certain medical products / devices or quasi-cosmetic products — and the potential dangers to those with allergies. 

The case concerns an Italian woman who was experiencing oral allergy symptoms — redness and swelling around lips and mouth. Patch testing found her positive to both MI/MCI and several common metal allergens, including nickel. 

Doctors traced the issue to her mouthwash, called Curasept®, which contained isothiazolinone preservatives, and which was marketed not as a cosmetic, but as a ‘medical device’. (Take care with this brand, incidentally, should you come across it. Some of their other oral care products contain MI, such as this toothpaste.)


What’s the difference?
A cosmetic is a preparation which moisturises, conditions, cleans, colours, perfumes or deodorises the part of the body on which it is applied, those parts including all external skin, hair and nails, and the oral cavity. A cosmetic is about improving appearance and condition; it’s about ‘beauty’. Cosmetics are legally bound to follow cosmetic laws, including those introduced with regards to permitted usage (or not) of MI and MCI. 

However, if a preparation serves a medical or ‘lifestyle’ purpose, it may not be classified as a cosmetic, and the associated laws may not apply as far as allergies are concerned. 


Cosmetic vs ‘Medical’ Mouthwash
Cosmetic mouthwash — the sort you might commonly find on a supermarket shelf — will serve only a cosmetic action, such as freshening (ie ‘deodorising’) breath.

But ‘medical’ mouthwash will serve additionally or principally as a curative. In the case of Curasept, this is described as a product for the “treatment of mouth ulcers, gingivitis, periodontitis, receding gums, care after oral surgery and caries”. That is medical, not cosmetic. 

As it happens, MI / MCI are permitted in cosmetic mouthwashes in the UK / Europe because they are ‘rinse off’ (or rinse out!) products, not ‘leave on’ cosmetic products, in which MI / MCI are banned. 

But as the paper in Contact Dermatitis tells us: “the current regulations concerning medical devices do not require the complete declaration of all the ingredients in the label”. 

This is unlike cosmetics, which requires full declaration of ingredients.

You can see how this might be a problem for those with (all) allergies. 


Further examples, and borderline products
Eye drops whose main role is to offer relief to tired or stinging eyes, or indeed for an eye infection, are not cosmetics — but mascara, eye liner and eye cream, all of which enhance the beauty of the eye area, and condition the skin respectively, are.

A vaginal douche is not a cosmetic, but a gentle wash for the vulva is.

Intimate lubricants are not usually classed as cosmetics … 

A hand cream is a cosmetic — as its function is to moisturise — but a hand sanitiser, whose function is to kill or protect from germs, is considered a biocide. However, a moisturising hand gel which also serves as a sanitiser could potentially fall into both camps, in which case it would be prudent to check what the primary purpose of the product is — if cosmetic, it should follow cosmetic laws, but if not, it might not. 

A topical muscle or joint gel for the treatment of pain or stiffness is unlikely to be a cosmetic unless, as above, it also serves a primary moisturising purpose, in which case it should be classed as a cosmetic, and be MI / MCI free in the UK and Europe. 

Medical ointments, for the treatment of eczema, for instance, are definitely not cosmetics, but I’ll return to this subject in a subsequent post. 


The bottom line
In a nutshell, if there is any doubt that a product for use on the body might not be a cosmetic, then remember that it may not be subject to cosmetic laws. 

Important: MI / MCI is banned in the UK / EU in leave-on COSMETICS, not necessarily on all leave-on PRODUCTS. 

In the US, I have found this document from the FDA which touches on this, but I hope to return to this on another occasion. If any US readers can shed further light, please leave a comment. Remember: MI / MCI remains permitted in leave-on cosmetics in the US, though I understand it has now been banned in Canada. 


  1. Winny

    Hi. I live in Canada and have not heard that Mi/MIC is banned in cosmetics. I find it in all lotions, sunscreens, liquid soaps, mascaras and laundry soaps. I stopped buying all of them eco max is the only laundry soap I use and I use vinegar foe fabric softner. I make my own toothpaste and lotions and dish wash soap. It is frustrating that a chemical so dangerous for a lot of people is still allowed on the market. I did not know that MI/MIC was banned only in cosmetics in europe. Thanks for the heads up, i will bring my own sheets on my trip.

    1. MI Free (Post author)

      I’ll check the Canada situation, but I was told very recently by a lady on Facebook (

      Do you have examples of Canadian sunscreens / mascaras with MI?

      MI / MCI is banned in *leave on* cosmetics in Europe – lotions, creams, make up – not ‘rinse off’ cosmetics (shampoo, shower gel)

      Laundry soap / fabric softener are not cosmetics.

    2. MI Free (Post author)

      Hi again Winny,

      Here is the link confirming MI / MCI banned in ‘leave on’ cosmetics in Canada:

      Best wishes, Alex.

  2. Lisa M Wolf

    Can you start a thread about allergic contact dermatitis that seems to occur mainly around the eyelash line, and what might contribute there?
    I’m hearing even plastic glasses can cause reactions?
    I’ve now changed over to “No Nothing” and “Jason” hair care and Faith In Nature body wash, Honest Baby Care lotions/face washes. No makeup for months now.

    Still finding my eyes a bit irritated. I was diagnosed with “dry eye” but I can’t find drops that don’t cause the reaction.

    This has been quite the journey.
    Thanks for any help.

    1. MI Free (Post author)

      Do you mean a thread on Facebook, Lisa?
      If you’re struggling with eye issues, it may even be worth seeing an optometrist for a check up – they can give lots of good advice.
      Is it only MI / MCI allergy you have? There could be other ingredients causing issues, depending on your patch test results.


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