Research on aromatherapy, a complementary alternative medicine in which oils from plants are absorbed into the body through massage or inhalation, was assessed. The studies generally used methods resulting in findings of reduced depression and anxiety that were compatible with causes other than aromatherapy. In the absence of rigorously controlled, well-designed studies comparable to those conducted in testing conventional medications, the conclusion that there is evidence of beneficial effects is unwarranted.
Since there is robust evidence that there are highly effective conventional medications, it is reasonable to conclude these should be tried prior to other treatments. However, if one is not using other medications and in the absence of physical conditions contraindicating aromatherapy, using the treatment is safe. There is a need for future studies that are capable of providing evidence that there are beneficial effects of aromatherapy, if the treatment actually has benefits.
Are there Beneficial Effects of Aromatherapy? The American Medical Association’s absolute requirement of meeting the Hippocratic Oath, “Do no harm,” should apply to any profession involved in medical or psychological treatment – conventional, alternative, or complementary alternative (Angell & Kassirer, 1999; Breen, 2003). Thus, the first and most important question to address regarding aromatherapy, the topic of this paper, was whether there are any circumstances under which the therapy can violate this Oath.
The second question was whether there was evidence that the therapy can be of value. In aromatherapy, individuals either inhale or are massaged with oils from plants which are absorbed into their bodies (Hemmer & Maker, 2005). Because of potential adverse reactions, the therapy is contraindicated in the presence of “pregnancy, epilepsy, local venous thrombosis, varicose veins, broken skin, recent surgery and circulatory disorders” (Ernst, 2006, p. 39).
As a professor of complementary medicine, Ernst’s review of such findings warrant withholding treatment from those with such conditions, as well as from those taking other medications which may be less effective when combined with aromatherapy (Ernst, 2006; Hemmer & Maker, 2005), especially since evidence of beneficial effects, as reported below, has been weak at best.
A major problem in assessing the effectiveness of alternative medicines in general (Angell & Kassirer, 1999) has been that they are legally used without evidence based on the controlled, well-designed clinical testing required for the approval of the Federal Drug Administration: “There cannot be two kinds of medicine – conventional and alternative. There is only medicine that has been adequately tested and medicine that has not, medicine that works and medicine that may or may not work” (p. 841).
The only requirement is that they not be described as “cures” – resulting in raising insinuation “to an art form of doublespeak” (p. 840). Resistance of those who practice alternative medicine to using “the best available methods of medical science” to test alternative treatments has raised questions in the medical community about the ethics of endorsing these treatments (Breen, 2003, p. 271).
These problems have contaminated research on aromatherapy, which has focused mainly on beneficial effects on mood, e. g. , depression, anxiety, agitation. First, however, based on a thorough multi-data-base search, what is most surprising is finding no study addressing what should be a crucial question: How does aromatherapy compare in influencing states such as depression and anxiety with what are now a large variety of traditional medications and “medication-cocktails” that have resulted from a virtual revolution over the past several decades in medical research in general (e. g. , (Osterberg & Bleschka, 2005).
If aromatherapy is found to be less effective, potential recipients of aromatherapy would be limited to those who have not been helped by traditional medications or who do not choose to try them. The only studies found on the effects of aromatherapy have some surprisingly obvious flaws. For example, Okamoto, et al. (2005) used a pre-post design, where depressed participants were assessed before and after receiving an aromatherapy message twice a day for four weeks. Reduced depression, as in all simple pre-post designs, should not have been attributed to treatment, as opposed to a shared event occurring between pre- and post testing (e. g. , depression in general might be affected by testing during a time of pleasant vs. unpleasant weather).
Buckle (2007) reviewed similar pre-post studies of the effects of aromatherapy on agitation in patients at health care centers for the elderly. In these studies, an additional weakness was that effectiveness was assessed informally by caregivers who knew first and second observations were of patients before and while receiving aromatherapy (i. e. , violating basic standards of assessment).