Recognition of the power of scent goes way back in history. Aromatherapy is rooted in ancient Egypt, India, Greece and Rome, where aromatic plants were used for religious, cosmetic and medical purposes. "Modern" aromatherapy was developed in the 1920's by the French chemist Rene-Maurice Gattefosse who did many experiments in aromatherapy on soldiers during World War I. It was partly because of him that aromatherapy took hold in Europe (Wartik 1995).
The term "aromatherapy" is actually something of a misnomer since, by most definitions, inhalation of fragrance isn't necessarily required. What defines aromatherapy is simply the use of certain oils: fragrant, highly concentrated substances produced by aromatic plants of trees as a means of, among other things, storing energy, repelling predators or attracting pollinating insects. These "essential" oils are massaged into the skin, dropped into a bath, or sometimes even taken orally (although most people don't recommend the latter). Since many other factors are involved when aromatherapy oils are used through massage or in a bath, (such as the healing touch of another person, or the soothing warmth of the bath water), for the purposes of this website, we are only going to focus on the uses and possible benefits of aromatherapy strictly through scent alone. The purpose of this section is lay out the facts of aromatherapy so that you can have the information you need to determine if this is something you might find helpful or just interesting.
Experimental Studies of the Beneficial Effects of Odor on Health
There are few studies demonstrating the beneficial effects of odor on human health. Most reports are in the form of anecdotal evidence rather than detailed experiments, which poses a problem when considering if the claims have any scientific basis. There have been reports by Watson and Rovesti suggesting the use of aromatic fumes for the treatment of mental disorders and for alleviating depression, however in common with many other studies of the type, they refer primarily to anecdotes (Martin 1996).
There is a historical precedent for the association between foul odor and ill-health however. Knasko (1992) reported that a group exposed to the odor of lemon reported significantly fewer symptoms of ill-health than a group exposed to unpleasant dimethyl sulfide. Malodour may also function as a 'survival mechanism' whereby the smell of decaying food, together with its appearance, warns a hungry organism of the potentially fatal consequences of ingesting the food (Martin 1996).
As for pleasant scents, there is no immediate, biological reason why pleasant scents might enhance physical well-being in the way that bad scents warn of danger. Because of this, there is not much literature relating to olfaction and its role in positively altering health. However, there have been some cases, again mostly anecdotal, showing a relationship between odor and health.
A summary of the findings is below:
The problem with all of these results is that often times they are only based on one or two cases and there are no statistical analyses, explicit methodology or subject details. This makes it hard to develop a standard or accepted treatment of illnesses through the use of scents.
Another problem with aromatherapy is that humans are very receptive to suggestion. If you are told that a certain scent will make you feel sleepy, you might actually feel sleepy just because you were told that's how you should feel. So the question is: what exactly brings about change in aromatherapy- the psychopharmacological effect of the odor, the individual's cognition or a combination of both?
More Definitive Findings
There has been some interesting findings that are more "scientific." It was found that chamomile can put people in a better mood (Roberts & Williams 1992) and lavender can help with temporary insomnia. Several of the odors used by aromatherapists are capable of producing physiological arousal as measured by electroencephalogram (EEG) recordings (Klemm et al. 1992); and emotional changes, as measured by self-report. Peppermint odor appears to be capable of causing very small EEG, elctromyogram (EMG), and heart rate changes during sleep (Badia et al. 1990). It has been shown that lavender increases alpha wave activity in the back of the brain, a sign of relaxation; jasmine increases beta wave activity in the front of the brain, indicating greater alertness (Wartik 1995).
A recent study by the Smell and Taste Treatment and Research Foundation in Chicago showed aromas to have a measurable impact on erotic response. Certain scents increased arousal levels in men, most notably a mixed lavender-and-pumpkin-pie smell, which proved more stimulation than traditionally sensuous scents, such as musk or oriental spice. These findings could possibly lead to impotence treatments.
The use of scent in weight loss programs could also prove to be promising. In one study it was reported that after nine weeks of pairing a patient's favorite food with an unpleasant odor, overweight patients showed a weight loss of over 13 pounds in comparison to 11 pounds for controls (the people who did not have a pairing of a food with a bad odor). At 48 weeks, the sample had lost 91 pounds whereas the controls had gained 11 pounds (Martin 1996). This could prove to be an effective therapy for weight loss.
A recent study done by an honor student here at Macalester looked at the relation of lavender scent to pain response. After taking baseline latencies in mice for a thermal stimulus (hotplate) she administered 10 drops of lavender into a water vaporizer twice daily to one group, while the other group only received the water vaporizer alone. She tested the hotplate latencies at 0 weeks, 1 week, 2 weeks, and 3 weeks and 4 weeks. Overall she found that the group which received treatment with lavender had significantly longer response times which ultimately means that they were analgesic (they didn't feel as much pain) (Lawton). These results suggest that lavender has properties which can reduce pain, however this was a very limited study because it only looked at one kind of pain. This study demonstrates that scientific experiments can be done on aromatherapy and other "complementary" therapies, which is very important because this is the only way that they will be accepted by the biomedical world. However, just because they are not accepted by the "scientific" people doesn't necessarily mean that it isn't useful.
Use it or Not?
In terms of practical usage, I would say that if you enjoy a certain smell than there is no reason that you shouldn't have that smell around you. It is your choice to decide or figure out how certain scents affect you, since smell is really quite a personal thing. You draw on your past experiences with particular scents, so perhaps lavender is calming for one person and to you it creates anxiety because when you were younger a lavender scent was what you smelled right before a dog attacked you. It's also important to realize that even though there is very little concrete scientific proof of the effects of scent on, for example, cancer, perhaps even if you believe it will help than you actually will see some effect whether it's due to the aromatherapy or your own natural healing mechanisms. And if you are feeling better than does it really matter how? Well for all of us scientists it does matter because we want to understand how it works, but if your aim is feel more relaxed or whatever the case may be, than I say, more power to you.
It's clear that smell is a powerful sense, and the idea that certain smells could physiologically effect us doesn't seem to be too farfetched. However, to claim that a certain scent will have a very specific effect and to give all the credit of that effect to only the scent rather than taking into account personal belief factors, is to deny part of the possible factors of any healing effect aromatherapy might have. More research needs to be done in order to figure out what is physiologically beneficial, but there is probably some truth in aromatherapy. It is considered a kind of folk medicine, and usually when something has centuries-long tradition behind it can't be all wrong.
So that's it. Make your decisions. Enjoy your sense of smell.
Suggested Effects of Scents
(Remember, scents don't always exert the same effect on everyone.)
(all of the above from Hammers 1995).
To me, these descriptions seem a bit vague. And they all seem remarkably similar as well. Kind of makes you wonder a little bit....
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