Among the complementary therapies, aromatherapy has an impressive history. It dates back as far as 2800 BC in ancient Egypt and was widespread in the Mediterranean region, with the earliest known distillation for extraction of essential oil from plant material being recorded by Herodotus in about 425 BC. During the Middle Ages the properties of aromatic plants were utilized to combat infectious diseases such as the plague; more recently, the Frenchman Gattefosse (often called the father of aromatherapy) used them to effect in the treatment of wounds of soldiers in the First World War. The art of distillation was developed to form the basis of alchemy, which has further developed into more technical chemistry. The use of herbal preparations and plant extracts is well established; the ‘active’ agents have been isolated and incorporated into many current pharmaceutical preparations. In aromatherapy training and practice in Britain, essential oils are administered to clients via inhalation, topical application and skin massages, and in baths. Interest in such techniques is stimulating research into the properties and actions of these oils and the development of aromatology. Aromatology additionally consists in administering oils internally by mouth, injections, pessaries and suppositories. Countries in which aromatology is practised, such as France, have practitioners who are also medically qualified. Specialized training courses are becoming increasingly popular in the UK. For reasons of safety it is not appropriate for aromatherapists to use essential oils internally on clients.