Toxicology of essential oils reviewed

Today there is an increasing need to gather and collect the toxicological data on the raw materials in order to calculate the potential irritancy of the materials contained in those products. We hope that the tables contained in these pages come at a time when many of us are scrabbling to collect LD50 values and other safety data in order to complete the more demanding Product Safety Report. We plan to keep this spreadsheet of information updated and will publish regular amendments as more information and essential oils are added. In order to ensure that this information grows we welcome readers to send any updates to the technical editor, who will add your name to a list of recipients who will be kept informed of any corrections or additions as they are made. We regret that only those people supplying additional data can be offered this service. 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.