I just received this reply from my personal aromatherapy expert ;-)

"Unfortunately Tisserand do use SLS in some of their products - the reason,
I
assume, is that Aromatherapy products are not monitored exclusively under
the Aromatherapy council but also by the Cosmetic and Beauty council - SLS
is derived from coconut oil and is used as a cheap way to make something
foam......Unfortunately in the bid to make Aromatherapy accessible to the
masses cheaper alternatives are used.

My suggestion would be to stop using the product - if your friend still
wants to use lavender oil in her bath can I suggest 2/3 drops of Lavender
essential oil mixed in the bath with a few tablespoons of milk (this will
stop the oil sitting on the surface and causing any reaction) or she can put
some oats in muslin with a few drops of lavender and hang this so the water
runs from the tap over it "Very Cleopatra" - she won't get a foam but will
get the benefits of the oil - or I can source an alternative for her."

--
Sacha
http://www.hillhousenursery.co.uk
South Devon
(remove weeds from address)
'We do not inherit the earth from our ancestors, we borrow it from our
children.'