Aromatherapy is the use essential oils to help us feel better emotionally, mentally, and physically. Some scents, such as frankincense, have a long history of spiritual use as well.
We actually breathe scent molecules into our bodies. Scents are processed by an ancient and instinctual part of our brain. We respond immediately and directly to them.
Synthetic "fragrance" oils are not suitable for use in aromatherapy, however pleasant some of them may be because their chemical makeup is different from that of an essential oil.
Some are steam-distilled. Citrus oils are pressed from peels. Other preparation methods are sometimes used. The end result is a pure, but very complex, mixture of volatile oils.