Its proponents state that aromatherapy uses the aromas of essential oils and other aromatic compounds from plants as a way to improve a person's mood and health.
Aromatherapists claim that this form of alternative medicine boosts the immune system, reduces stress and pain, and restores or enhances mental, emotional, physical, and spiritual health.
Researchers at Ohio State University decided to put this brand of alternative medicine to the test. They asked 56 young, healthy volunteers to sniff either lemon oil, or lavender, or distilled water for periods of almost four hours, on each of three different days.
Half the participants were told which aromatic substance they would be smelling on a given day and what kinds of effects to expect; the other half were not told what they were smelling or what to expect.
Surprisingly, the investigators did find that lemon oil genuinely lifted mood. In a number of physical, psychological, and laboratory evaluations, however, no other differences were detected between sniffing distilled water and sniffing the real odorants.
Physical measures included pulse and blood-pressure effects; pain sensations and hormone responses while the feet were immersed in cold water; and skin healing after tape stripping (where adhesive tape is applied to the skin surface and then quickly removed).
The researchers also used several questionnaires to evaluate participants' mood and emotional responses. Blood tests examined immunological responses and levels of cortisol, epinephrine, and norepinephrine, three hormones involved in the fight-or-flight response.
Despite aromatherapists' claims that lavender and lemon oil boost the immune system, at least one immune reaction was actually boosted more by sniffing distilled water than by breathing in either of these odorants.
The findings were the same whether the participants were blinded or not and whether or not they had been frequent users of aromatherapy before entering the study.
One of the authors of the study, which was published in the April issue of Psychoneuroendocrinology, said, "This is probably the most comprehensive study [of aromatherapy] ever done ...."
These results are enough to reinforce my previous belief that aromatherapy is useless. Fairness, however, requires me to mention that positive effects might have been found if different aromas had been tested or if other measures of response had been used.
And, in case anyone believes I've given aromatherapy short shrift here, and am basing my conclusions on a single study of 56 people, I should note that I've been to the Web site of the National Center for Complementary & Alternative Medicine (NCCAM) and looked around there for information and news about aromatherapy.
The NCCAM site has very little to say about lavender — "There is little scientific evidence of lavender's effectiveness for most health uses" ... "Small studies on lavender for anxiety show mixed results" — and nothing whatsoever to say about lemon oil.
Clicking on the site's hotlink to "Aromatherapy" turned up nothing except a mention of the same Ohio State study discussed above (but without mentioning the study's results).
