22/11/2023
Essential oils and aromatic herbs have an important relationship with what TCM calls wei qi, or “defense qi.” Because of their germ-fighting and immuno-supportive powers, and because they are so effective when used for atmospheric purification when diffused, essential oils are one of the primary media for strengthening wei qi and treating what is described as “invasion of wind affecting the surface of the body,” specifically, threats to the respiratory system.
Aromatic herbs, when used internally, are a key treatment for supporting the qi and yang of the Spleen; clearing dampness and stagnation from the digestive system; and strengthening the respiratory system through their qi circulating, decongestant, and expectorant actions.
That is why the majority of aromatic herbs used in TCM are used for either releasing the exterior and dispersing exterior wind conditions (of the respiratory system), or warming and dispersing dampness and stagnation in the digestive system. The active principles of these species are the volatile aromatic oils.
Aromatherapy using essential oils is a primary treatment for many kinds of shen disturbances in TCM. There are many fascinating reasons for this, which stem from the relationship between the sense of smell and the limbic, endocrine, and neurological systems. Specifically, aroma has a strong and direct influence on the centers of the brain related to emotion, memory, and circadian rhythms, meaning that the smells we perceive have a direct link to the neurochemistry underlying shen disturbances.
The term shen is a somewhat intangible concept compared to modern diagnostic criteria. I was taught that it has to do with the light in the eyes, which is a rather difficult quality to evaluate objectively! It’s also related to a person’s overall emotional affect, whether they had a positive or negative attitude and demeanor and is sometimes translated as “Spirit.” I learned that someone with a positive and bright shen had a stronger immune system than someone whose shen was dull, so I’ve come to understand it as a kind of psycho-neuro-immunology.