Essential oils are complex materials. They are extracted from many different plant species and subsequently have many different therapeutic properties for aromatherapy use. However, some plant species produce chemotypes; that is an essential oil that may be extracted from the same plant species but chemically it is composed differently. Essential oil chemotypes introduce you to the chemistry of essential oils and how different chemical components can alter how an essential oil can be used.
It is a complex area but also an important one if you are to understand the chemistry of essential oils 🙂 Some chemotypes may be high in alcohols whereas other essential oil chemotypes may be high in the more volative component of phenols.
To learn more, I wrote the following article as an introduction to this complex chemistry area of aromatherapy: