Use as a room freshener or for an instant aromatherapy pick-me-up, these non-aerosol mists contain 100% pure essential oils. Essential Oil Basics Essential oils are the highly concentrated, volatile, aromatic essences of plants. Scientists agree that essential oils may perform more than one function in living plants. In some cases they seem to be a part of the plant's immune system. In other cases they may simply be end-products of metabolism. Essential oils contain hundreds of organic constituents, including hormones, vitamins and other natural elements that work on many levels. They are 75 to 100 times more concentrated than the oils in dried herbs. All the countries of the world provide essential oils, making aromatherapy a truly global therapy. Not all Oils are Created Equal Some plants, like rose and jasmine, contain very little essential oil. Their important aromatic properties are extracted using a chemical solvent. The end product, known as an absolute, contains essential oil.