Abstract

The use of aromatic plants and the oils derived from them dates back at least 6500 years in Egypt, 4500 years in China, and 3000 years in India, and perhaps much further back than those estimates. Most plant essential oils used today on a commodity scale are obtained by hydrodistillation, a process first attributed to the Persian physician Ali-Ibn Sana (also known as Avicenna), who lived 1000 years ago. Essential oils from Citrus peels are obtained by cold pressing, and a handful of other essential oils are obtained via extraction with lipophilic solvents.