Toxicology of essential oils reviewed

 It was also quite clear that there were a great number of reported contraindications that had no foundation, for example, whether or not to use an essential oil during pregnancy. There also seemed to be confusion between the effect of essential oils used topically and those that might be ingested. A full introduction to the subject of toxicology of essential oils, plus spreadsheets of data, were published in the September 2009 issue of Personal Care Asia Pacific. Further spreadsheets of data are published on the following pages of this, November, issue. The presented data is just the beginning of a long journey and we hope that readers will feel inspired to help us to fill in the gaps, offer additional values or other useful information in order that we can make this a living document. We are working with other researchers in the field of essential oils (e.g. Tony Burfield at Cropwatch and others) to expand this knowledge and to protect the industry from the ever increasing attack from those who would restrict or ban essential oils (based sometimes on the presence of a single molecule). We will be allowing a number of relevant organisations to publish the full spreadsheet information on their websites in the hope that we can prevent media scare stories e.g. pre-puberty boys presenting gynaecomastia (condition in teenage boys where firm, tender breast tissue grows under the nipples) supposedly following the use of lavender oil.

Background

It has always been a challenge to find out the toxicological profile of essential oils and despite some excellent reference works on the topic, there has never been a single reference that supplied all the required data. Sadly, many of the books published on the topic of aromatherapy have not been written by scientists or toxicologists and this has meant that there is a great deal of poor quality information circulating which has propagated and found its way on to the internet. The use of the phrase “not tested on animals” is not only illegal but is also totally without truth, since in all nearly all cases these essential oils have been tested on animals at one time or another in the past. The LD50 value (lethal dose 50%) using animals (usually based on rats or mice) gives a value for the death of half the animals tested, so that an LD50 of 2 g/kg refers to the total weight of material tested/body mass of test animal that caused death in half the number tested. Thus, if a human weighed 70 kg then it might be expected that 140 g could be consumed before it was fatal. The idea that because a material is natural it therefore must be safe could not be further from reality. There are essential oils that are so toxic that they should never be consumed or applied to the skin without extreme caution. The risks of sensitisation, irritation, phototoxicity or being an abortifacient are fact. Essential oils contain a rich blend of highly functional molecules some of which are beneficial and others which are not.