Essential oils have been used for thousands of years. Hippocrates claimed that the way to health was through aromatic baths and massages. Much anecdotal evidence exists regarding aromatherapy's positive effects on recipients. However, well-designed research trials are sparse. Certainly much controversy exists regarding the appropriate way to conduct research on holistic therapies. Can their effects be broken down and studied without contradicting the central premise on which holism is based? The purpose of this article is to review the current state of the science of aromatherapy and to propose future research. The author also offers guidelines for safe aromatherapy practice while awaiting future research on its clinical efficacy.