For thousands of years, people have been distilling and processing certain plant materials to extract their powerful healing essences. In medieval Latin, a theory of this famous physician, Paracelsus, referred to the oils he distilled from medicinal plants as the quinta essentia – the quintessence of the plant were the most active parts of a tree, shrub, plant or flower. This theory formed the basis for further investigations and experiments into the beneficial medical use of ‘Quinta Essentia” and that is where the term ‘Essential Oil’ comes from.