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Introduction |
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Aromatic oils have been used for therapeutic purposes for nearly six thousand
years (Buckle 2000). The ancient Chinese, Indians, Egyptians, Greeks, and Romans
employed essential oils derived from plant materials in cosmetics, perfumes, and
pharmaceuticals. Today, aromatherapy is gaining new attention as an alternative
healing modality related to herbal medicine (Buckle 2000; Stevensen
1996). |
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Historical Background |
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Archeological evidence found in King Tutenkhamun's tomb and during
excavations of the Indus Valley clearly demonstrates that essential oils were
used during those times. The Old and New Testaments, written records from the
ancient Greek physician Hippocrates, and European herbal texts also reveal that
essential oils were employed commonly for spiritual, therapeutic, hygienic, and
ritualistic purposes (Stevensen 1996).
René-Maurice Gattefossé, a French chemist, discovered the healing properties
of lavender oil when he applied it to a burn on his hand after an explosion in
his laboratory. Following this incidental finding, he devoted his time to
analyzing the chemical properties of essential oils and to documenting their
therapeutic value in treating burns, skin infections, gangrene, and wounds in
soldiers during World War I (Stevensen 1996). In 1928, Gattefossé founded the
science of aromatherapy (Buckle 2000; Buckle 1999; Stevensen 1996). In the
1950s, Marguerite Maury expanded the applications of aromatherapy in France to
include uses by massage therapists, beauticians, nurses, physiotherapists,
conventional doctors, and other healthcare professionals, an influence that
continues to this day (Stevensen 1996). In France, more than 1,500 trained
physicians employ essential oils as an alternative to antibiotics (Buckle
2000).
This alternative modality did not become widely known in the United States
until the 1980s, when essential oils gained the attention of massage therapists,
alternative practitioners, and the commercial industry. The lotions and beauty
products currently sold under the guise of aromatherapy, however, usually
contain synthetic fragrances, which lack the therapeutic components found in
essential oils (Buckle 2000). While aromatherapy is one of the fastest growing
complementary modalities, its commercial use and connection to the cosmetic
industry has created some confusion about its therapeutic potential (Buckle
2000; Stevensen 1996). For instance, candles are frequently made with synthetic
fragrances and called "aromatherapy." (Buckle 2000). |
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Scientific
Principles |
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Essential oils, which contain volatile organic compounds, are extracted from
plants, flowers, wood resins, and citrus peels by a process of steam
distillation using petrochemical solvents (Buckle 1999). In the past decade,
several books have been published that include current research on the chemical
constituents and therapeutic actions of each oil. For instance, aldehydes have
anti-infectious properties, C10 terpenes have a cortisone-like action, esters
have an antispasmodic action, ketones are mucolitic and litholitic, oxides have
expectorant and antiparasitic qualities, phenols stimulate the immune system,
and sesquiterpenes are antihistamines (Stevensen 1996). |
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Mechanism of Action |
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The chemical components found in essential oils have both physiologic and
psychologic properties; they work on a molecular level and can be administered
in a variety of ways. When inhaled, the nose detects the scent and transmits it
to the olfactory bulb, which sends nerve impulses to the limbic system in the
brain, including both the amygdala, which controls emotions, and the
hippocampus, which stores and retrieves memories. Lavandula angustifolia,
for example, an essential oil with sedative and pain relieving properties, is
believed to affect the amygdala by increasing inhibitory neurons containing
g-aminobutyric acid (GABA); if accurate, this is the
same process by which the medication diazepam produces sedation and reduces the
effect of external stimuli such as pain. Aromatic chemicals trigger the
repository of stored memories in the hippocampus, which can have measurable
effects on mood; for example, there are cases of depressed, elderly,
institutionalized individuals reporting decreased sadness after smelling certain
fruits and flowers that triggered childhood memories. When applied to the skin,
essential oils are absorbed into the bloodstream. Occasionally, essential oils
are also ingested, but this is considered a component of herbal medicine and
should only occur while one is under the guidance of a qualified specialist
(Buckle 1999).
In addition to the mechanisms described above, studies suggest that essential
oils relieve pain and induce mood changes through several other methods. First,
analgesic compounds, such as 1,8-cineole (eucalyptol), activate the brain to
release neurotransmitters such as dopamine, serotonin, and norepinephrine.
Essential oils such as cardamon, rosemary, and eucalyptus contain eucalyptol.
When essential oils are administered topically as part of a massage, the direct
touch stimulates sensory fibers in the skin, which triggers the parasympathetic
nervous system, thus inducing relaxation and decreasing the perception of pain
(Buckle 1999). Essential oils also impact brain wave activity, creating either
stimulating or sedative effects (Stevensen 1996). |
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Clinical Evaluation |
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For topical or inhalant uses, patients may consult professional
aromatherapists, as well as nurses, physical therapists, and massage therapists
trained in the external use of essential oils; only specially trained
professionals can provide treatment for the internal use of essential oils
(Buckle 2000). A typical visit includes a discussion of the patient's medical
history, presenting complaint(s), and aromatic preferences, as choices of scents
are partially based on one's likes and dislikes (Buckle 1999).
Depending upon the condition, patients may be instructed to inhale essential
oils either directly by placing a few drops on a piece of cloth, or indirectly
through steam inhalations, vaporizers, or sprays. Small quantities
(approximately one to five drops) can also be diluted with carrier oils and
applied topically in the form of compresses or massage oils. Mixed with milk or
cream, they can be added to baths. Some of the therapies may be applied during
the clinical evaluation; in most cases, patients also are given instructions on
how to continue to use the therapy at home (Buckle 1999). |
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Clinical Applications |
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Scientific literature supports the use of essential oils for insomnia; in
addition, several randomized, controlled clinical trials have demonstrated a
reduction of pain medication for people with rheumatoid arthritis, cancer, and
headaches (Buckle 1999). One randomized, double-blind, controlled trial
indicates that thyme, rosemary, lavender, and cedar-wood oils may promote hair
growth in people with alopecia areata (Hay et al. 1998); other essential oils
improve skin conditions in those with psoriasis (Walsh 1996).
An eight-year clinical trial that collected prospective data from more than
8,000 women who employed aromatherapy during labor and delivery showed promising
results. A qualified midwife aromatherapist administered essential oils in the
form of inhalations, massages, footbaths, and a drop on the brow or palm during
established labor or in the latent phase. The results indicate that rose,
lavender, and frankincense oils may reduce feelings of anxiety and fear,
improving a women's overall well-being during childbirth, as well as reducing
the need for epidural analgesia or other pain medication. Many women report that
peppermint oil is effective in relieving nausea and vomiting,
common symptoms during labor that frequently are exacerbated by the use
of epidural analgesia. Additionally, clary-sage oil may strengthen contractions
and decrease the need for oxytocin in women with dysfunctional labor (Burns et
al. 2000).
When applied topically, some chemical compounds, including tea tree, have
antibacterial and anti-fungal properties (Hay et al. 1998). There is some
suggestion in the literature that citrus oils may enhance immune function
(Buckle 2000) and that peppermint oil may inhibit the activity of the
gastrointestinal smooth muscle, reducing abdominal spasms and digestive
disorders (Stevensen 1996). Fennel, aniseed, sage, and clary-sage have
estrogen-like compounds that resemble the action of estradiol and balance
hormone production, which may make them effective in relieving symptoms
associated with premenstrual syndrome, menopause, and the menstrual cycle
(Buckle 2000). A randomized, double-blind, crossover study of headache patients
treated with topical applications of peppermint essential oil found that the
therapy had a significant analgesic effect. In addition, a randomized study of
51 patients with cancer found that massages with chamomile essential oil
produced statistically significant reductions in tension, anxiety, and pain
(Buckle 1999). |
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Risks, Side Effects, Adverse
Events |
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Most of the commonly used essential oils have been tested by the food and
perfume industries and hold GRAS (generally regarded as safe) status (Buckle
2000). However, the solvents used in the extraction and distillation processes
may cause allergic or sensitizing reactions in certain individuals (Buckle
1999). One occasionally reported side effect is headache (Burns et al. 2000).
Although extremely rare, essential oils also have been reported to cause contact
dermatitis (Weiss and James 1997). Rare adverse events include abortifacient
effects, impaired liver function, and neurotoxicity due to the high quantity of
ketones in certain oils, such as Lavandula stoechas (Stevensen 1996).
Given that essential oils contain pharmacologically active ingredients, some
may, theoretically, interact with medications, providing either synergistic or
negative effects. While this area of study has not been adequately investigated
in humans, animal studies indicate that eucalyptol may significantly decrease
the effect of phenobarbital and that West Indian lemongrass may potentiate the
effect of morphine (Buckle 1999). Other essential oils, such as bergamot, can
cause photosensitivity and burns if patients are exposed to sunlight after
topical application (Buckle 2000).
Patients should obtain essential oils from reputable suppliers listed with
aromatherapy organizations. There can be some adulteration in the production of
essential oils (mainly diluting them with cheaper, less effective oils) and the
quality of plants can vary depending on the source and growing conditions. In
addition, different species of plants vary in terms of potency; therefore, oils
should be selected on the basis of the botanical, not the common, name (Buckle
2000).
As mentioned previously, essential oils should never be ingested unless a
patient is explicitly instructed to do so by a trained professional; some oils
are toxic and taking them orally could be fatal. Oils that are high in phenols,
such as cinnamon, can cause dermal irritation. In order to avoid potential
reactions, patients should dilute oils before use and avoid using them near the
eyes. In addition, essential oils are highly volatile and flammable; they must
not be used near an open flame (Buckle 2000). |
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Contraindications |
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Patients with hypertension should avoid using stimulating essential oils,
such as rosemary and spike lavender (Buckle 1999). Emmenogogic oils, such as
hyssop, should be avoided throughout pregnancy; hyssop oil also should be
avoided in patients with a history of seizures. In general, all essential oils
should be avoided during the first trimester of pregnancy and in patients with
severe asthma or a history of multiple allergies. Patients with
estrogen-dependent tumors should not use oils with estrogen-like compounds such
as fennel, aniseed, sage, and clary-sage. Practitioners should exercise caution
when using essential oils with patients undergoing chemotherapy (Buckle
2000). |
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Additional Clinical
Outcomes |
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Although more research is required, there are anecdotal reports of the
successful use of essential oils to treat acne, anorexia, anxiety, autism,
borderline hypertension, bronchitis, burns, chronic pain, constipation,
cystitis, depression, diabetic ulcers, idiopathic infertility, indigestion,
insomnia, irritable bowel syndrome, low back pain, memory loss, migraines, mild
asthma, muscle pain, nausea, orthostatis, osteoarthritis, premenstrual syndrome,
psoriasis, sinusitis, sports injuries, staphylococcal skin infections, stress,
substance abuse, water retention, and bacterial, viral, and fungal infections.
In addition, children with autism, behavioral problems, colic, diaper rash, and
sleep problems may benefit from the nonverbal stimuli of smell and touch, which
facilitate communication at a basic level. Essential oils also may be an
effective adjunct modality for problems affecting the elderly, such as memory
loss, dry skin, bed-sores, and Alzheimer's disease (Buckle 2000). Research on
mice suggests that sandalwood decreases skin papillomas (Hay et al.
1998). |
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The Future |
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Although essential oils have been used for millennia, few controlled clinical
trials have been conducted in human beings. While there are many potential uses
of aromatherapy in a wide variety of settings, conclusive evidence of its
clinical efficacy is lacking (Buckle 2000). Additionally, there are some
concerns regarding the safety and quality of certain essential oils (Stevensen
1996). More research is necessary before aromatherapy becomes a widely accepted
alternative modality with clear and specific clinical indications (Buckle
2000). |
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Training, Certification, and
Licensing
Requirements |
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Training courses to become an aromatherapist generally range from one weekend
to several years; there are no prerequisites prior to participating in the
curriculum and there is currently no licensing procedure. People who take the
courses tend to be massage therapists, registered nurses, and physical
therapists. At present, there is no recognized national certification
examination, although Educational Standards in Aromatherapy in the United States
is in the process of establishing the Aromatherapy Registration Board as a
nonprofit governing body that will administer a national standardized exam and
provide the public with a list of registered practitioners (Buckle 2000).
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Resources |
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For a directory of aromatherapy schools and practitioners, contact the
National Association for Holistic Aromatherapy, P.O. Box 17622, Boulder, CO
80308, 888-ASK-NAHA, www.naha.org. The trade association that publishes the
quarterly Journal of Aromatherapy is the American Alliance of
Aromatherapy, P.O. Box 750428, Petaluma, CA 94975-0428.
Certification courses are offered by the American Aromatherapy Association,
P.O. Box 3679, South Pasadena, CA: Aromatherapy Seminars, 3379 South Robertson
Blvd., Los Angeles, CA 90034; The Pacific Institute of Aromatherapy, P.O. Box
6842, San Rafael, CA 94903. |
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References |
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Buckle J. Aromatherapy. In: Novey DW, ed. Clinician's Complete Reference
to Complementary and Alternative Medicine. St. Louis, Mo: Mosby;
2000:651-666.
Buckle J. Use of aromatherapy as a complementary treatment for chronic pain.
Altern Ther Health Med. 1999;5(5):42-51.
Burns EE, Blamey C, Ersser SJ, Barnetson L, Lloyd AJ. An investigation into
the use of aromatherapy in intrapartum midwifery practice. J Altern
Complement Med. 2000;6(2):141-147.
Hay IC, Jamieson M, Ormerod AD. Randomized trial of aromatherapy: successful
treatment for alopecia areata. Arch Dermatol. 1998;134:1349-1352.
Stevensen CJ. Aromatherapy. In: Micozzi MS, ed. Fundamentals of
Complementary and Alternative Medicine. New York, NY: Churchill Livingstone
Inc.; 1996:137-148.
Walsh D. Using aromatherapy in the management of psoriasis. Nurs Stand.
1996;11(13-15):53-56.
Weiss RR, James WD. Allergic contact dermatitis from aromatherapy. Am J
Contact Dermat.
1997;8(4):250-251. |
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Copyright © 2000 Integrative Medicine
Communications This publication contains
information relating to general principles
of medical care that should not in any event be construed as specific
instructions for individual patients. The publisher does not accept any
responsibility for the accuracy of the information or the consequences arising
from the application, use, or misuse of any of the information contained herein,
including any injury and/or damage to any person or property as a matter of
product liability, negligence, or otherwise. No warranty, expressed or implied,
is made in regard to the contents of this material. No claims or endorsements
are made for any drugs or compounds currently marketed or in investigative use.
The reader is advised to check product information (including package inserts)
for changes and new information regarding dosage, precautions, warnings,
interactions, and contraindications before administering any drug, herb, or
supplement discussed herein. | |