The term essential oil originates from the Latin "Quinta Essentia" which means "the quintessence of plant". Essential oils are oils present in flowers, fruit, roots, leaves, seeds, bark or aromatic plants. The oils consist of tiny odoriferous droplets. They have a very wide range of aromas and colours from red, brown, blue and yellow to green. Besides being used in aromatherapy, essential oils are also used in perfumes, pharmaceuticals and as food flavourings. Essential oils, however, are more than just fine aromas. They have a complex chemical composition that can provide valuable psychological and physical therapeutic benefits.

The sense of smell is directly linked to the brain. Inhaled aromas are registered by the limbic system of the brain which is the centre of emotions, memory and learning. The olfactory nerve is located inside the nose and responds to specific aromas. It sends the olfactory information to the seat of emotions and memory in the brain. This area connects with another part of the brain (hypothalamus and pituitary gland) which controls the hormonal system. The aromas from essential oils trigger a wide range of chemical reactions within the body, including the release of specific chemicals. This explains why aromas have such a powerful impact on our mood and general state of mind.