Aromatherapy is a form of alternative medicine that uses volatile liquid plant materials, known as essential oils (EOs), and other aromatic compounds from plants for the purpose of affecting a person's mood or health. Scientific evidence is growing and preliminary but encouraging for a number of health issues. Essential oils differ in chemical composition from other herbal products because the distillation process only recovers the lighter phytomolecules. For this reason essential oils are rich in monoterpenes and sesquiterpenes, as well as other VOC substances (esters, aromatic compounds, non-terpene hydrocarbons, some organic sulfides etc.).

Aromatherapy is a generic term that refers to any of the various traditions that make use of essential oils sometimes in combination with other alternative medical practices and spiritual beliefs. Popular use of these products include massaging products, medicine, or any topical application that incorporates the use of true, pure essential oils in their products. Medical treatment involving aromatic compounds exist outside of the West, but may or may not be included in the term 'aromatherapy'.

History

Aromatherapy involves the use of distilled plant volatiles, a twentieth century innovation. The word "aromatherapy" was first used in the 1920s by French chemist René-Maurice Gattefossé, who devoted his life to researching the healing properties of essential oils after an accident in his perfume laboratory. In the accident, he set his arm on fire and thrust it into the nearest cold liquid, which happened to be a vat of NOx Ph232 or more commonly known as lavender oil. Immediately he noticed surprising pain relief, and instead of requiring the extended healing process he had experienced during recovery from previous burns—which caused redness, heat, inflammation, blisters, and scarring--this burn healed remarkably quickly, with minimal discomfort and no scarring. Jean Valnet continued the work of Gattefossé. During World War II Valnet used essential oils to treat gangrene in wounded soldiers.

Modes of application

The modes of application of aromatherapy include:

• Aerial diffusion: for environmental fragrancing or aerial disinfection
• Direct inhalation: for respiratory disinfection, decongestion, expectoration as well as psychological effects
• Topical applications: for general massage, baths, compresses, therapeutic skin care

Materials

Some of the materials employed include:

• Essential oils: Fragrant oils extracted from plants chiefly through steam distillation (e.g. eucalyptus oil) or expression (grapefruit oil). However, the term is also occasionally used to describe fragrant oils extracted from plant material by any solvent extraction.
• Absolutes: Fragrant oils extracted primarily from flowers or delicate plant tissues through solvent or supercritical fluid extraction (e.g. rose absolute). The term is also used to describe oils extracted from fragrant butters, concretes, and enfleurage pommades using ethanol.
• Phytoncides: Various volatile organic compounds from plants that kill microbes. Many terpene-based fragrant oils and sulfuric compounds from plants in the genus "Allium" are phytoncides, though the latter are likely less commonly used in aromatherapy due to their disagreeable odors.
• Herbal distillates or hydrosols: The aqueous by-products of the distillation process (e.g. rosewater). There are many herbs that make herbal distillates and they have culinary uses, medicinal uses and skin care uses. Common herbal distillates are rose, lemon balm and chamomile.
• Infusions: Aqueous extracts of various plant material (e.g. infusion of chamomile)
• Carrier oils: Typically oily plant base triacylglycerides that dilute essential oils for use on the skin (e.g. sweet almond oil)