Proponents of aromatherapy report that aromatic or essential oils have been used for thousands of years as stimulants or sedatives of the nervous system and as treatments for a wide range of other disorders. [1] They link it historically to the use of infused oils and unguents in the Bible and ancient Egypt,[1] remedies used throughout the Middle Ages and the Renaissance,[2] and the burning of aromatic plants in various primitive religious rites. The current applications of aromatherapy did not come about until the early 20th century when the French chemist and perfumer Rene Gattefosse coined the term “aromatherapy” and published a book of that name in 1937.[2] Gattefosse proposed the use of aromatherapy to treat diseases in virtually every organ system, citing mostly anecdotal and case-based evidence.[2]

Although Gattefosse and his colleagues in France, Italy, and Germany studied the effects of aromatherapy for some 30 years, its use went out of fashion midcentury and was rediscovered by another Frenchman, a physician, Jean Valnet, in the latter part of the century. Valnet published his book The Practice of Aromatherapy in 1982,[3] at which time the practice became more well-known in Britain and the United States. Through the 1980s and 1990s, as patients in Western countries became increasingly interested in complementary and alternative medicine (CAM) treatments, aromatherapy developed a following that continues to this day. In addition to the growing use of essential oils by nurses and aromatherapy practitioners for specific medical issues, the popularity of aromatherapy has also been exploited by cosmetics companies that have created lines of essential oil-based (though often with a synthetic component) cosmetics and toiletries, claiming to improve mood and well-being in their users.

Despite the growing popularity of aromatherapy in the latter part of the 20th century (especially in the United Kingdom), little research on aromatherapy was available in the English-language medical literature until the early or mid-1990s. The research that began to appear in the 1990s was most often conducted by nurses, who tended to be the primary practitioners of aromatherapy in the United States and United Kingdom (although it is dispensed by medical doctors in France and Germany). Aromatherapists now publish their own journal, the International Journal of Essential Oil Therapeutics. Also, many studies regarding the effects of odor on the brain and other systems in animals and healthy humans have been published in the context of odor psychology and neurobiology (and in the absence of the specific term aromatherapy).

In addition to topical antibacterial uses,[4] aromatherapy has also been proposed for use in wound care [5] and to treat a variety of localized symptoms and illnesses such as alopecia, eczema, and pruritus. [6-10] Aromatherapy has also been studied via inhalation for airway reactivity.[11]

Studies on aromatherapy have examined a variety of other conditions: sedation and arousal;[12,13] startle reflex and reaction time;[14,15] psychological states such as mood, anxiety, and general sense of well-being;[16-31] neurologic impairment;[24] chronic renal failure;[25] agitation in patients with dementia;[32-36] smoking withdrawal symptoms;[37,38] postoperative nausea; [39] nausea and emesis in combination with fatigue, pain, and anxiety in patients in labor;[26,27,40] pain alone;[41-43] and pain in combination with other symptoms.[23,24,26,27]

Published articles have described the use of aromatherapy in specific hospital settings such as cancer wards, hospices, and other areas where patients are critically ill and require palliative care for pain, nausea, generalized stress, and anxiety.[44] These observational studies provide examples of the clinical uses of aromatherapy (and other CAM modalities), though they are generally not evidence-based. Subjects have included hospitalized children with HIV, [45] homebound patients with terminal disease,[46] and hospitalized patients with leukemia. [47] Studies of aromatherapy use with mental health patients have also been conducted.[48,49] Most of the resulting articles describe successful incorporation of aromatherapy into the treatment of these patients, though outcomes are clearly subjective.

Theories about the mechanism of action of aromatherapy and essential oils differ, depending on the community studying them. Proponents of aromatherapy often cite the connection between olfaction and the limbic system in the brain as the basis for the effects of aromatherapy on mood and emotions; less is said about proposed mechanisms for its effects on other parts of the body. Most of the aromatherapy literature, however, lacks in-depth neurophysiological studies on the nature of olfaction and its link to the limbic system, and it generally does not cite research that shows these links. Proponents of aromatherapy also believe that the effects of the treatments are based on the special nature of the essential oils used. Some authors propose that the extraction of essential oils from whole aromatic plants causes them to contain a life force or vitality that allegedly sets essential oils apart from other (synthetic) fragrances.[50] This argument suggests that essential oils produce effects on the body that are greater than the sum of the individual chemical components of the scents.

These assertions have been contested by the biochemistry and psychology communities, which take a different view of the possible mechanism of action of odors on the human brain (most do not differentiate the odors produced by essential oils from those of synthetic fragrances).[50] This neurobiological view, which focuses mostly on the emotional and psychological effects of fragrances (as opposed to the other symptomatic effects claimed by aromatherapists), takes into account what is known about olfactory transduction and the connection of the olfactory system to other central nervous system functions; however, it is primarily theoretical because of the lack of significant research addressing this topic.

References

1. Tisserand R: Essential oils as psychotherapeutic agents. In: Van Toller S, Dodd GH, eds.: Perfumery: The Psychology and Biology of Fragrance. New York, NY: Chapman and Hall, 1988, pp 167-80. 
   
   
2. Gattefosse RM: Gattefosse's Aromatherapy. Essex, England:CW Daniel, 1993. 
   
   
3. Valnet J: The Practice of Aromatherapy: A Classic Compendium of Plant Medicines & Their Healing Properties. Rochester, NY: Healing Arts Press, 1990. 
   
   
4. Dryden MS, Dailly S, Crouch M: A randomized, controlled trial of tea tree topical preparations versus a standard topical regimen for the clearance of MRSA colonization. J Hosp Infect 56 (4): 283-6, 2004.  [PUBMED Abstract]
   
   
5. Hartman D, Coetzee JC: Two US practitioners' experience of using essential oils for wound care. J Wound Care 11 (8): 317-20, 2002.  [PUBMED Abstract]
   
   
6. Baker J: Essential oils: a complementary therapy in wound management. J Wound Care 7 (7): 355-7, 1998.  [PUBMED Abstract]
   
   
7. Asquith S: The use of aromatherapy in wound care. J Wound Care 8 (6): 318-20, 1999.  [PUBMED Abstract]
   
   
8. Hay IC, Jamieson M, Ormerod AD: Randomized trial of aromatherapy. Successful treatment for alopecia areata. Arch Dermatol 134 (11): 1349-52, 1998.  [PUBMED Abstract]
   
   
9. Anderson C, Lis-Balchin M, Kirk-Smith M: Evaluation of massage with essential oils on childhood atopic eczema. Phytother Res 14 (6): 452-6, 2000.  [PUBMED Abstract]
   
   
10. Ro YJ, Ha HC, Kim CG, et al.: The effects of aromatherapy on pruritus in patients undergoing hemodialysis. Dermatol Nurs 14 (4): 231-4, 237-8, 256; quiz 239, 2002.  [PUBMED Abstract]
    
    
11. Cohen BM, Dressler WE: Acute aromatics inhalation modifies the airways. Effects of the common cold. Respiration 43 (4): 285-93, 1982.  [PUBMED Abstract]
    
    
12. Diego MA, Jones NA, Field T, et al.: Aromatherapy positively affects mood, EEG patterns of alertness and math computations. Int J Neurosci 96 (3-4): 217-24, 1998.  [PUBMED Abstract]
    
    
13. Motomura N, Sakurai A, Yotsuya Y: Reduction of mental stress with lavender odorant. Percept Mot Skills 93 (3): 713-8, 2001.  [PUBMED Abstract]
    
    
14. Miltner W, Matjak M, Braun C, et al.: Emotional qualities of odors and their influence on the startle reflex in humans. Psychophysiology 31 (1): 107-10, 1994.  [PUBMED Abstract]
    
    
15. Millot JL, Brand G, Morand N: Effects of ambient odors on reaction time in humans. Neurosci Lett 322 (2): 79-82, 2002.  [PUBMED Abstract]
    
    
16. Stevenson C: Measuring the effects of aromatherapy. Nurs Times 88 (41): 62-3, 1992 Oct 7-13.  [PUBMED Abstract]
    
    
17. Dunn C, Sleep J, Collett D: Sensing an improvement: an experimental study to evaluate the use of aromatherapy, massage and periods of rest in an intensive care unit. J Adv Nurs 21 (1): 34-40, 1995.  [PUBMED Abstract]
    
    
18. Buckle J: Aromatherapy. Nurs Times 89 (20): 32-5, 1993 May 19-25.  [PUBMED Abstract]
    
    
19. Hadfield N: The role of aromatherapy massage in reducing anxiety in patients with malignant brain tumours. Int J Palliat Nurs 7 (6): 279-85, 2001.  [PUBMED Abstract]
    
    
20. Wilkinson S: Aromatherapy and massage in palliative care. Int J Palliat Nurs 1 (1): 21-30, 1995. 
    
    
21. Wilkinson S, Aldridge J, Salmon I, et al.: An evaluation of aromatherapy massage in palliative care. Palliat Med 13 (5): 409-17, 1999.  [PUBMED Abstract]
    
    
22. Corner J, Cawler N, Hildebrand S: An evaluation of the use of massage and essential oils on the wellbeing of cancer patients. Int J Palliat Nurs 1 (2): 67-73, 1995. 
    
    
23. Louis M, Kowalski SD: Use of aromatherapy with hospice patients to decrease pain, anxiety, and depression and to promote an increased sense of well-being. Am J Hosp Palliat Care 19 (6): 381-6, 2002 Nov-Dec.  [PUBMED Abstract]
    
    
24. Walsh E, Wilson C: Complementary therapies in long-stay neurology in-patient settings. Nurs Stand 13 (32): 32-5, 1999 Apr 28-May 4.  [PUBMED Abstract]
    
    
25. Itai T, Amayasu H, Kuribayashi M, et al.: Psychological effects of aromatherapy on chronic hemodialysis patients. Psychiatry Clin Neurosci 54 (4): 393-7, 2000.  [PUBMED Abstract]
    
    
26. Burns E, Blamey C: Complementary medicine. Using aromatherapy in childbirth. Nurs Times 90 (9): 54-60, 1994 Mar 2-8.  [PUBMED Abstract]
    
    
27. Burns EE, Blamey C, Ersser SJ, et al.: An investigation into the use of aromatherapy in intrapartum midwifery practice. J Altern Complement Med 6 (2): 141-7, 2000.  [PUBMED Abstract]
    
    
28. Kite SM, Maher EJ, Anderson K, et al.: Development of an aromatherapy service at a Cancer Centre. Palliat Med 12 (3): 171-80, 1998.  [PUBMED Abstract]
    
    
29. Komori T, Fujiwara R, Tanida M, et al.: Effects of citrus fragrance on immune function and depressive states. Neuroimmunomodulation 2 (3): 174-80, 1995 May-Jun.  [PUBMED Abstract]
    
    
30. Wiebe E: A randomized trial of aromatherapy to reduce anxiety before abortion. Eff Clin Pract 3 (4): 166-9, 2000 Jul-Aug.  [PUBMED Abstract]
    
    
31. Lehrner J, Eckersberger C, Walla P, et al.: Ambient odor of orange in a dental office reduces anxiety and improves mood in female patients. Physiol Behav 71 (1-2): 83-6, 2000 Oct 1-15.  [PUBMED Abstract]
    
    
32. Ballard CG, O'Brien JT, Reichelt K, et al.: Aromatherapy as a safe and effective treatment for the management of agitation in severe dementia: the results of a double-blind, placebo-controlled trial with Melissa. J Clin Psychiatry 63 (7): 553-8, 2002.  [PUBMED Abstract]
    
    
33. Smallwood J, Brown R, Coulter F, et al.: Aromatherapy and behaviour disturbances in dementia: a randomized controlled trial. Int J Geriatr Psychiatry 16 (10): 1010-3, 2001.  [PUBMED Abstract]
    
    
34. Holmes C, Hopkins V, Hensford C, et al.: Lavender oil as a treatment for agitated behaviour in severe dementia: a placebo controlled study. Int J Geriatr Psychiatry 17 (4): 305-8, 2002.  [PUBMED Abstract]
    
    
35. Gray SG, Clair AA: Influence of aromatherapy on medication administration to residential-care residents with dementia and behavioral challenges. Am J Alzheimers Dis Other Demen 17 (3): 169-74, 2002 May-Jun.  [PUBMED Abstract]
    
    
36. Cohen-Mansfield J, Werner P: The effects of an enhanced environment on nursing home residents who pace. Gerontologist 38 (2): 199-208, 1998.  [PUBMED Abstract]
    
    
37. Rose JE, Behm FM: Inhalation of vapor from black pepper extract reduces smoking withdrawal symptoms. Drug Alcohol Depend 34 (3): 225-9, 1994.  [PUBMED Abstract]
    
    
38. Sayette MA, Parrott DJ: Effects of olfactory stimuli on urge reduction in smokers. Exp Clin Psychopharmacol 7 (2): 151-9, 1999.  [PUBMED Abstract]
    
    
39. Tate S: Peppermint oil: a treatment for postoperative nausea. J Adv Nurs 26 (3): 543-9, 1997.  [PUBMED Abstract]
    
    
40. Oyama H, Kaneda M, Katsumata N, et al.: Using the bedside wellness system during chemotherapy decreases fatigue and emesis in cancer patients. J Med Syst 24 (3): 173-82, 2000.  [PUBMED Abstract]
    
    
41. Dale A, Cornwell S: The role of lavender oil in relieving perineal discomfort following childbirth: a blind randomized clinical trial. J Adv Nurs 19 (1): 89-96, 1994.  [PUBMED Abstract]
    
    
42. Göbel H, Schmidt G, Soyka D: Effect of peppermint and eucalyptus oil preparations on neurophysiological and experimental algesimetric headache parameters. Cephalalgia 14 (3): 228-34; discussion 182, 1994.  [PUBMED Abstract]
    
    
43. Marchand S, Arsenault P: Odors modulate pain perception: a gender-specific effect. Physiol Behav 76 (2): 251-6, 2002.  [PUBMED Abstract]
    
    
44. Buckle J: Clinical Aromatherapy: Essential Oils in Practice. 2nd ed. New York, NY: Churchill Livingston, 2003. 
    
    
45. Styles JL: The use of aromatherapy in hospitalized children with HIV disease. Complement Ther Nurs Midwifery 3 (1): 16-20, 1997.  [PUBMED Abstract]
    
    
46. Rimmer L: The clinical use of aromatherapy in the reduction of stress. Home Healthc Nurse 16 (2): 123-6, 1998.  [PUBMED Abstract]
    
    
47. Stringer J: Massage and aromatherapy on a leukaemia unit. Complement Ther Nurs Midwifery 6 (2): 72-6, 2000.  [PUBMED Abstract]
    
    
48. Hicks G: Aromatherapy as an adjunct to care in a mental health day hospital. J Psychiatr Ment Health Nurs 5 (4): 317, 1998.  [PUBMED Abstract]
    
    
49. Mantle F: The role of alternative medicine in treating postnatal depression. Complement Ther Nurs Midwifery 8 (4): 197-203, 2002.  [PUBMED Abstract]
    
    
50. Dodd GH: The molecular dimension in perfumery. In: Van Toller S, Dodd GH, eds.: Perfumery: The Psychology and Biology of Fragrance. New York, NY: Chapman and Hall, 1988, pp 19-46. 
    
    

Glossary Terms

A condition in which a person is unable to relax and be still. The person may be very tense and irritable, and become easily annoyed by small things. He or she may be eager to have an argument, and be unwilling to work with caregivers to make the situation better.

The lack or loss of hair from areas of the body where hair is usually found. Alopecia can be a side effect of some cancer treatments.

An incomplete description of the medical and treatment history of one or more patients. Anecdotal reports may be published in places other than peer-reviewed, scientific journals.

A substance that kills bacteria or stops them from growing and causing disease.

Feelings of fear, dread, and uneasiness that may occur as a reaction to stress. A person with anxiety may sweat, feel restless and tense, and have a rapid heart beat. Extreme anxiety that happens often over time may be a sign of an anxiety disorder.

A type of complementary and alternative medicine that uses plant oils that give off strong pleasant aromas (smells) to promote relaxation, a sense of well-being, and healing.

Having an odor, which often is pleasant or spicy.

The state of being alert and ready to respond, or waking from sleep.

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord. Also called malignancy.

A detailed report of the diagnosis, treatment, and follow-up of an individual patient. Case reports also contain some demographic information about the patient (for example, age, gender, ethnic origin).

The brain and spinal cord. Also called CNS.

A disease or condition that persists or progresses over a long period of time.

Having to do with the examination and treatment of patients.

Forms of treatment that are used in addition to (complementary) or instead of (alternative) standard treatments. These practices generally are not considered standard medical approaches. Standard treatments go through a long and careful research process to prove they are safe and effective, but less is known about most types of CAM. CAM may include dietary supplements, megadose vitamins, herbal preparations, special teas, acupuncture, massage therapy, magnet therapy, spiritual healing, and meditation. Also called CAM.

A condition in which a person loses the ability to think, remember, learn, make decisions, and solve problems. Symptoms may also include personality changes and emotional problems. There are many causes of dementia, including Alzheimer disease, brain cancer, and brain injury. Dementia usually gets worse over time.

In medicine, a disturbance of normal functioning of the mind or body. Disorders may be caused by genetic factors, disease, or trauma.

A group of conditions in which the skin becomes inflamed, forms blisters, and becomes crusty, thick, and scaly. Eczema causes burning and itching, and may occur over a long period of time. Atopic dermatitis is the most common type of eczema.

Vomiting.

The scented liquid taken from certain plants using steam or pressure. Essential oils contain the natural chemicals that give the plant its “essence” (specific odor and flavor). Essential oils are used in perfumes, food flavorings, medicine, and aromatherapy.

A condition marked by extreme tiredness and inability to function due lack of energy. Fatigue may be acute or chronic.

A pleasant, sweet odor.

The cause of acquired immunodeficiency syndrome (AIDS). Also called human immunodeficiency virus.

A program that provides special care for people who are near the end of life and for their families, either at home, in freestanding facilities, or within hospitals.

A method of putting fluids, including drugs, into the bloodstream. Also called intravenous infusion.

In medicine, refers to the act of taking a substance into the body by breathing.

Cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of blood cells to be produced and enter the bloodstream.

A network of structures in the brain involved in memory and emotions.

Restricted to the site of origin, without evidence of spread.

A person’s overall psychological and emotional condition. Good mental health is a state of well-being in which a person is able to cope with everyday events, think clearly, be responsible, meet challenges, and have good relationships with others.

A method of treatment. For example, surgery and chemotherapy are treatment modalities.

A feeling of sickness or discomfort in the stomach that may come with an urge to vomit. Nausea is a side effect of some types of cancer therapy.

The organized network of nerve tissue in the body. It includes the central nervous system (the brain and spinal cord), the peripheral nervous system (nerves that extend from the spinal cord to the rest of the body), and other nerve tissue.

Having to do with nerves or the nervous system.

A health professional trained to care for people who are ill or disabled.

A type of study in which individuals are observed or certain outcomes are measured. No attempt is made to affect the outcome (for example, no treatment is given).

A smell.

The sense of smell.

The parts of the body involved in sensing smell, including the nose and many parts of the brain. Smell may affect emotion, behavior, memory, and thought.

A series of events in which cells in the nose bind to scent-bearing molecules and send electrical signals to the brain where they are perceived as smells.

A part of the body that performs a specific function. For example, the heart is an organ.

Care given to improve the quality of life of patients who have a serious or life-threatening disease. The goal of palliative care is to prevent or treat as early as possible the symptoms of a disease, side effects caused by treatment of a disease, and psychological, social, and spiritual problems related to a disease or its treatment. Also called comfort care, supportive care, and symptom management.

After surgery.

Itching. Severe itching may be a side effect of some cancer treatments and a symptom of some types of cancers.

A condition in which the kidneys stop working and are not able to remove waste and extra water from the blood or keep body chemicals in balance. Acute or severe renal failure happens suddenly (for example, after an injury) and may be treated and cured. Chronic renal failure develops over many years, may be caused by conditions like high blood pressure or diabetes, and cannot be cured. Chronic renal failure may lead to total and long-lasting renal failure, called end-stage renal disease (ESRD). A person in ESRD needs dialysis (the process of cleaning the blood by passing it through a membrane or filter) or a kidney transplant. Also called kidney failure.

A drug or substance used to calm a person down, relieve anxiety, or help a person sleep.

In medicine, a family of drugs used to treat depression, attention-deficit disorder (a common disorder in which children are inattentive, impulsive, and/or over-active), and narcolepsy (a sleep disorder that causes uncontrollable sleepiness). Stimulants increase brain activity, alertness, attention, and energy. They also raise blood pressure and increase heart rate and breathing rate.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

Having to do with symptoms, which are signs of a condition or disease.

Having to do with substances that are man-made instead of taken from nature.

Disease that cannot be cured and will cause death.

On the surface of the body.

A substance used on the skin to soothe or heal wounds, burns, rashes, scrapes, or other skin problems. Also called ointment.

A break in the skin or other body tissues caused by injury or surgical incision (cut).