Essential oils are generally very complex chemically, containing many different substances and compounds. Some experts have theorized that essential oils are the lifeblood of a plant, and contain compounds that the plant uses to fight infections and drive away germs and parasites. Scientific research has isolated hundreds of chemicals in essential oils, and has shown many essential oils to have anti-bacterial, anti-fungal, and anti-parasitic properties.
Some essential oils contain over 200 identified chemical substanes.