According to allure.com, "Essential oils are highly concentrated, volatile plant extracts obtained through different extraction methods, including steam distillation, which is the purification of a liquid via heating. A few popular elixirs include rose oil (which is derived from actual rose petals), lavender oil, and tea tree oil." Currently, there are 300 essential oils available for purchase and they can be used in many ways. They can be used for cleaning, applied topically, and inhaled.