Aromatherapy was discovered, quite by accident, by French chemist Reme Gattefosse in the 1920's.  After accidentally setting his arm on fire, he plunged it into a vat of lavender oil.  He experienced immediate pain relief and fast healing with very little discomfort and no scarring.  With all of his previous burns, he had redness, inflammation, heat, blisters and scarring associated with them.  In France, aromatherapy is now incorporated into mainstream medicine.  Some essential oils are considered to be a prescription drug and must be prescribed by a physician.  Aromatherapy is the technique used to determine which essential oil to use on a case-by-case basis.  After culturing a patient's infected tissue or secretion, it is divided between Petri dishes that have been supplied with agar.  Each individual Petri dish is then inoculated with a different essential oil to isolate which one has the most activity against that particular strain of microorganism.  This activity will manifest as a pattern of inhibited growth. Even though in many countries essential oils are included in the national pharmacopeia, the United States, Russia, Germany and Japan have never recognized aromatherapy as a valid branch of medicine.   

Aromatherapy is the use of liquid plant materials (essential oils) to affect a person's mood or health.  It can help ease aches, pains and injuries and also relieve the discomfort of many health problems.  It acts on the central nervous system to help relieve depression, anxiety, and stress.  It can also produce a calming, uplifting, sedating or stimulating effect and help to restore physical and emotional well-being.  By using the appropriate oil, aromatherapy can have a powerful effect on both the body and spirit however, artificially made substitutes for Pure Essentials Oils can not produce the same effect.  Essential oils activate the olfactory center in the nose and a particular part of the brain by their scent.  They activate the thermal receptors and kill microbes and fungi when applied to the skin, usually in the form of massage oils.  They may also stimulate the immune system with internal application as in the use of pharmacological drugs.  Essential oils are very potent and may irritate the skin or cause toxic reactions such as liver damage and seizures unless diluted with carrier oils (oily plant base triacylglycerides used to dilute essential oils for use on the skin).  Some oils that are used in the dilution are sweet almond oil, olive oil, hazelnut oil, rosehip seed oil, lemon balm and chamomile.  Phototoxic reactions can occur with some citrus oils such as lime or lemon. 

Popular essential oils: 

Basil:  Increased concentration, relief of headaches and migraines, help with depression.  (Do not use during pregnancy)  

Bergamot:  Most popular perfume oil, insect repellent, helpful with urinary and digestive tract.  Also for stress related skin conditions such as cold sores and chicken pox. (Especially useful when combined with eucalyptus oil). 

Black Pepper:  Used for stimulating the circulation and for muscular aches and pains.  Because it stimulates the circulation, it is also useful for bruises. 

Citronella Oil:  Used as an insect repellent and in perfumes. 

Clove Oil:  Used as a topical analgesic and is especially useful in dentistry. 

Jasmine, Rose, Sandalwood and Ylang Ylang:  Used as aphrodisiacs. 

Lavender Oil:  Used as an antiseptic will soothe cuts, burns, headaches, and migraines and is also used to calm and relax. 

Mint:  Used for relief of the airways in cases of colds and flu. 

Tea Tree Oil:  Used as antiseptics and disinfectants. 

Yarrow Oil:  Used to reduce joint inflammation and also to relieve cold and flu symptoms.