The man credited with some of the founding research on the clinical value of
essential oils Rene-Gattefosse, did not think that the terpene content of natural
oils was beneficial for the skin. He makes reference to this in his book and in
the 1950s he produced several articles for the perfumery trade where he re-
emphasised this belief.

UNREFINED FIXED OILS

Many modern aromatherapists recommend crude wheatgerm oil for damaged
skin. However, this crude extract can contain viable fungal spores. Any such
unrefined plant materials will contain fungal spores because they are present in
high concentrations in old barns, the air, or are naturally present on the plant
materials. These spores are inert in the fixed oil, but as soon as water and
humidity is introduced - such as occurs in wounds or cosmetic formulations -
then these spores can and do come to life.

Crudely prepared fixed oils can contain bacterial toxins. Garlic infused in fixed
oil and ingested was responsible for a number of deaths in the USA and as the
result laws now require such oils are pasteurised. Such toxins applied to
intact skin should not cause a problem, but it would not be wise to apply them
to broken skin.

With already traumatised tissue, the introduction of irritating substances such
as viable fungal spores, is likely to produce over-granulation of the wound.
This is because the body is trying to protect itself against the invading
organisms.

UNRECTIFLED ESSENTIAL OILS

Removal of some of the terpenes from distilled lavender oil has a number of
advantages:

1. The terpenes are probably of little therapeutic value.

2. The odour components are frequently found in the minor non-terpene
fractions of essential oils.

3. Any trace chemical compounds with therapeutic actions will become
concentrated by the reduction of terpenes.

4. Rectification and redistillation tends to “clean up” the naturally occurring
irritating or sensitising chemicals present in essential and fixed oils.

5. Natural does not always equal safe or beneficial
 

Source and copyright: aromamedical.org