Our sense of smell starts in the olfactory epithelium of our nose. An odour can chemically stimulate cell receptors there, sending a signal to tissue deep within our central nervous system for interpretation.
Olfaction is processed in a portion of the brain also involved with emotions, learning, and memory. The Limbic System, as it is known, records memories of our behaviours and our experiences, good or bad.
Aromatherapy has its roots in understanding that smell has the potential to reach deep neural tissue, and may affect emotional and cognition neural centers nearby.
Essential Oils are used in aromatherapy. Some oils are inhaled, some are used on the skin, and some oils are even approved by Health Canada for internal use.