Essential oils stimulates the powerful sense of smell. It is known that odors we smell have a significant impact on how we feel. In dealing with patients who have lost the sense of smell, doctors have found that a life without fragrance can lead to high incidence of psychiatric problems such as anxiety and depression. We have the capability to distinguish 10,000 different smells. It is believed that smells enter through cilia (the fine hairs lining the nose) to the limbic system, the part of the brain that controls our moods, emotions, memory and learning.

Studies with brain wave frequency has shown that smelling lavender increases alpha waves in the back of the head, which are associated with relaxation. Fragrance of Jasmine increases beta waves in the front of the head, which are associated with a more alert state.

Scientific studies have also shown that essential oils contain chemical components that can exert specific effects on the mind and body. Their chemistry is complex, but generally includes alcohols, esters, ketones, aldehydes, and terpenes. The effect of these chemical components are summarized in the accompanying table.

Each essential oil contains as much as 100 chemical components, which together exert a strong effect on the whole person. Depending on which component is predominating in an oil, the oils act differently. For example, some oils are relaxing, some soothes you down, some relieves your pain, etc. Then there are oils such as lemon and lavender, which adapt to what your body needs, and adapt to that situation. (These are called "adaptogenic"). The mechanism in which these essential oils act on us is not very well understood. What is understood is that they affect our mind and emotions. They leave no harmful residues. They enter into the body either by absorption or inhalation.

A fragrance company in Japan conducted studies to determine the effects of smell on people. They have pumped different fragrances in an area where a number of keyboard entry operators were stationed and monitored the number of mistakes made as a function of the smell in the air. The results were as follows:

• When exposed to lavender oil fragrance (a relaxant), the keyboard typing errors dropped 20 percent.
  
• When exposed to jasmine (an uplifting fragrance), the errors dropped 33 percent.
  
• When exposed to lemon fragrance (a sharp, refreshing stimulant), the mistakes fell by a whopping 54 percent!