physical reactions. Many people have experienced a particular smell bringing back both good and bad memories. We are now fairly certain that the newborn baby locates its mothers breast by smell. This is an area of odour perception deserving much greater scrutiny. The overuse of fragrant products by a mother might destroy baby's perception of who its mother is. Some researchers are suggesting that the reason women who occupy the same area tend to synchronise menstrual cycles, is because of minute traces of body pheromones. Rarely are these odiferous molecules consciously detectable, yet they are registered by our olfactory system and trigger real physiological processes. Research has detected changes in brain waves during sleep caused by the introduction of fragrance. In this connection, hospitals should think much harder about the effects of smell on unconscious patients. The effects may be good or bad depending on the odour being perceived by the brain. Experiments have been conducted on humans, where fragrances were administered at such low levels, that the subjects said "they could not smell them". Yet, brain waves changed, indicating that the fragrance molecules were still being detected by the olfactory apparatus. Clearly, the sense of smell has major importance. However, there is also an increasing body of knowledge showing that significant volumes of the aromatic constituents of essential oils are absorbed into the blood stream via the respiratory tract.  Therefore, a dual effect looks highly likely as follows: 1) A pharmacological action by the absorption of aromatic chemicals via the respiratory tract. 2) An indirect, yet powerful effect on the brain via olfactory perception. It may be seen therefore, that whether an essential oil is partly synthetic may not matter as far as olfactory perception is concerned. However, if there is also a pharmacological action via inhalation, then it is unwise to introduce to the body significant amounts of impure fragrance chemicals. The issue of

impurities in synthetic fragrance chemicals cannot be overestimated. The chemicals used to compound perfumes are often only

'laboratory grade' and contain significant impurities. It is partly because of those impurities, that expert analysts can tell if an essential oil has been adulterated. We should also not forget that the volumes of these impurities may be only 1-2%, but dioxins are hazardous in parts per billion.