It is another form of herbal medicine. Only oils distilled from plant material can be called essential. They are not greasy and they evaporate readily. When heated they quickly turn from liquid to vapor. They can penetrate fatty tissue rapidly and enter the bloodstream through the skin almost immediately.
Essential oils contain hundreds of very complex parts including vitamins and hormones.
They are a hundred times more concentrated than herbs and they have a profound physical effect on the body. The name essential in this case, means the essence or beginning spark of life. Ancient Arabian physicians were always searching for the essence or beginning spark of life. They believed that if they could reduce living material, like plants, down to almost nothing, where all that was left was the tiny spark that was the beginning of the life of the plant, they would have a magic substance that would cure illness and restore youth. They were the inventors of the first distillation techniques some 5,000 years ago and the first producers of crude essential oils.