Aroma Therapy is a subset of herbal medicine and it falls under Alternative Medicine.
Aromatherapy uses a series of fragrant plant oils. It is believed that the aroma from these plant oils promote physical and emotional well-being. These plant oils are also called as essential oils, and are now being used in soaps and cosmetics. There are some practioners who combile aromatherapy with ayurvedic massage, but adding these plant oils along with the herbal oil used for massage.
However the most common form treatment involves inhaling the essential oils. For wider usage these essential oils are diluted using carrier oils.
Method of functioning:
When the essential oils are inhaled the molecules (that are actually responsible for the aroma) travel inside the nose and activates the olfactory nerves. That will in turn stimulate certain parts of the brain resulting in various physical and emotional effects.
Aromatherapy is widely used today and it is an important part of Alternative medicine that is being practiced in North America.