An essential oil is defined as a volatile part of a natural product, which can be obtained by distillation, steam distillation or expression in the case of citrus fruits. It contains mostly volatile hydrocarbons. Essential oils are derived from various sections of plants. The oil is "essential" in the sense that it carries a distinctive scent, or essence of the plant.

Further support can be found through the European Federation of Essential Oils (EFEO) and International Fragrance Association (IFRA).

Sectoral guidance for essential oils

The European Federation of Essential Oils (EFEO) and the International Fragrance Association (IFRA) has published guidance for characterising essential oils. The limited number of language versions available on ECHA's website is due to the limited number of essential oil producing member states. Follow this guidance when you are identifying essential oils for REACH and CLP purposes.