As early as 1904 Cuthbert Hall had shown that the antiseptic power of eucalyptus oils in its natural form was stronger than its isolated main active constituent, 'eucalyptol' or 'cineol'. Other French doctors and scientists used essential oils as a part of a program to successfully treat specific medical and psychiatric disorders, to which the results became published in 1964 as 'Aromatherapie'. On the first two points, aromatherapy has much in common with the tradition of medical herbalism- in other words, it is not simply the aroma that is important but also the chemical interaction between the oils and the body, and the physical changes that are brought about. Air-borne aromatic oil molecules interact with the systems of the body. Odor signals are passed directly to the limbic system brain evoking an immediate emotional or instinctual response.
Aromatic molecules enter the lungs and are absorbed via the alveoli into the blood.
The blood is carried to the heart and transported throughout the body via the circulatory system. Different oils have affinities with specific parts of the body-e.g. Waste and toxins are processed by the liver and kidneys and eliminated mainly via the lungs, but also in the urine and sweat.