Essential oils are concentrated extracts of the volatile, non-water soluble aroma compounds from plants.

Essential oils are mixtures of many different compounds.

Essential oils are widely used in perfumes, cosmetic products, cleaning products and as flavourings in foods.

Terpenes are unsaturated compounds formed by joining together isoprene (2-methylbuta-1,3-diene) units.

Terpenes are key components in most essential oils.

Terpenes can be oxidised within plants to produce some of the compounds responsible for the distinctive aromas of spices.