According to Dr. Schnaubelt, the chemical makeup of essential oils gives them a quantity of desirable pharmacological properties ranging from antibacterial, antiviral, and antispasmodic, to uses as diuretics (promoting production and excretion of urine), vasodilators (widening blood vessels), and vasoconstrictors (narrowing blood vessels). Essential oils act on the adrenals, ovaries, and the thyroid and can energize or pacify, detoxify, and facilitate the digestive process. The oils' therapeutic properties also make them effective for treating infection, interacting with the various branches of the nervous system, modifying immune response, and harmonizing moods and emotions.

The Physiological Effects of Fragrance

  John Steele, Ph.D., of Sherman Oaks, California, and Robert Tisserand, of London, England, leading researchers in the field of aromatherapy, have studied the effects on brain wave patterns when essential oils are breathed in or smelled. Their findings show that oils such as orange, jasmine, and rose have a tranquilizing effect and work by altering the brain waves into a rhythm that produces calmness and a sense of well-being. In the same way, the so-called "stimulating" oils-basil, black pepper, rosemary, and cardamom-work by producing a heightened energy response.

  Breathing in the fragrance of certain essential oils can help clear sinuses or free congestion in the chest, and alter the neurochemistry of the brain to produce changes in mental and emotional behavior. Even aromas too subtle to be consciously detected can have significant effects on central nervous system activity, sometimes to the point of cutting in half the amount of time needed to perform a visual search task.