The oils are made through a distillation or cold pressing from the plant’s flowers, leaves, branches, bark, rind, or roots. The oils are then mixed with a "carrier" — usually a vegetable oil such as soy, primrose, or almond — or diluted in alcohol before being applied to the skin, sprayed in the air, or inhaled.

The very name "aromatherapy" implies some sort of medical benefit, but a new study published in the British Journal of General Practice says that there is little evidence that the aromatherapy has any specific health effects, although it is not without its benefits.

Researchers examined 12 clinical aromatherapy studies conducted over the past 18 years. Six involved aromatherapy combined with therapeutic massage. The other studies looked at medical interventions for smoking withdrawal, bronchitis, baldness, and other applications. Researchers found all the studies had small patient samples and were flawed. Still, researchers found that 10 of the 12 studies indicated some positive results for aromatherapy, though few concluded that there were strong, clear-cut benefits. The most consistent finding was that therapeutic massages using essential oils may have a slightly more relaxing effect in the short term than massages without them.

Massage therapists decide on which oil to use by asking individuals how they feel. For example, a fatigued person may be advised to use eucalyptus. Individual effects vary. Lavender, for instance, is calming for some people, uplifting for others. The oils apparent effects seem to be derived from the quick "assimilation" into the bloodstream. But the British researchers say the five massage studies that showed beneficial effects made no claim about whether skin absorption of the oils was the reason — or whether it was just that they smelled good.

The researchers may never know why aromatherapy may have some beneficial effects. Perhaps certain scents trigger relaxing memories, which trigger positive results. Whatever relief oils provide, their effects seem to release an emotional response, and gaining control of emotional responses to disease and everyday stress is a vital part of maintaining wellness. The technique can be used as a comforting ritual to reduce stress, enhance relaxation, and relieve anxiety, relieve psychosomatic symptoms, insomnia, and lessen the effects of emotionally-related disorders. However, medical science can find no physical reason for these effects — but that doesn’t mean it doesn’t enhance feelings of well-being.

Although there are individuals who provide "aromatherapy," many people simply use the oils as a home remedy. Please know that there is a notable lack of agreement on such issues as the amount of oil necessary to achieve a desired effect, the most effective method of administration, and the length of time necessary to continue treatment. Nonetheless, some of the more typical approaches involve inhalation, diffusion, massage, bathing, hot and cold compresses, explained below.

Inhalation: Use 6 to 12 drops of essential oil to a bowl of steaming water. Place a towel over your head. Deeply breathe the scented vapors.

Diffusion: Spray scents into the air. Said to calm nerves and promote feelings of well-being. Add 10 drops of an essence to 7 tablespoonfuls of water.

Massage: Aromatic oils rubbed into the skin may either calm or stimulate. It depends on the oil. Preparations contain about 5 drops of an essential oil mixed with a light base oil. Be careful, higher concentrations can irritate the skin.

Bathing: Use no more than 8 drops in a tubful of water, about 5 drops in a foot bath, or 3 to 4 drops to a hand bath (for chapped skin). Do not use this technique if you have any skin allergies.

Hot and cold compresses: For muscle aches or pains, bruises, or headaches add 5 to 10 drops of oil to about 4 ounces of water. Soak a cloth in the mixture. Apply the cloth to the sore area.

Uses for Essential Oils

Regardless of the many claims made for aromatherapy, proponents do assign specific areas of benefit to essential oils. Below are basic descriptions of their qualities.

Lavender: Heals burns and cuts; destroys bacteria; relieves depression, inflammation, spasms, headaches, respiratory allergies, muscle aches, nausea, menstrual cramps; soothes bug bites; lowers blood pressure.

Peppermint: Alleviates digestive problems; cleans wounds; decongests the chest; relieves headache, neuralgia, and muscle pain; useful for motion sickness.

Eucalyptus: Lowers fever; clears sinuses; has antibacterial and antiviral properties; relieves coughs; useful for boils and pimples.

Tea Tree: Fights fungal, yeast, and bacterial infections; useful for skin conditions such as acne, insect bites, and burns; helps clear vaginitis, bladder infections, and thrush.

Rosemary: Relieves pain; increases circulation; decongests the chest; relieves pain, indigestion, gas, and liver problems; lessens swelling; fights infection; helps alleviate depression.

Chamomile: Reduces swelling; treats allergic symptoms; relieves stress, insomnia, and depression; useful in treating digestive problems.

Thyme: Lessens laryngitis and coughs; fights bladder and skin infections; relieves digestive problems and pain in the joints.

Tarragon: Stimulates digestion; calms neural and digestive tracts; relieves menstrual symptoms and stress.