The art - and science - of using plant oils in treatment. Aromatherapy is a truly holistic therapy, taking account of the mind body and spirit of the person seeking help, as well as their lifestyle, eating patterns, relationships, etc.
Although the word aromatherapy was first used in the present century (maybe we ought to spell it 'aromatherapie' in this contect as the originator was a Frenchman) to describe the use of essential oils from plants as a form a treatment, the principles on which it is based are very, very old.
Aromatherapy has its roots in the most ancient healing practices of humankind, for the plants from which we now derive essential oils had been used for thousands of years before the technique of distilling oils was discovered. Archaeologists have found traces of many plants of known medicinal value in the burial places and living sites of early humans (the plants can be identified by analysis of the fossilised pollen), and it is very unlikely that their users knew nothing of their healing properties, even if these were stumbled across by accident in the first place.
The earliest people probably discovered by chance that some of the leaves, berries and roots they gathered for food made sick people feel better, or that their juices helped wounds to heal. They probably also observed the plants that sick animals chose to eat. Such knowledge would have been very precious to people who depended entirely on the resources in their immediate environment and, once discovered, would be handed down within the tribe as part of their shared wisdom.