Essential Oil Research...

Enjoy the essential oil research below! The research shows a variety of positive effects for a number of health concerns including infections, pain, anxiety, depression, tumors, premenstrual syndrome, nausea, and many others. It is categorized into five sections for your convenience.

Benencia, F. (1999). Antiviral activity of sandalwood oil against Herpes simplex viruses-1 and -2. Phytomedicine 6(2), 119-23.

The study tested the antiviral activity of sandalwood oil, the essential oil of Santalum album L against Herpes simplex virus type 1 (HSV-1) and 2 (HSV-2). Results demonstrated dose- dependent effect of sandalwood oil in inhibiting the replication of virus, and more significantly against HSV-1. The results also indicate a possible chemopreventive action of sandalwood oil against carcinogenesis.

Pain Relief

Burns, E., Zobbi, V., Panzeri, D., Oskrochi, R., Regalia, A. (2007). Aromatherapy in childbirth: a pilot randomized controlled trial. BJOG: An International Journal of Obstetrics & Gynaecology, 114(7), 838-44.

This study of 513 mothers aimed to determine the feasibility of conducting a randomized controlled trial on the use of aromatherapy during labor as a care option that could improve maternal and neonatal outcomes. Pain perception was reduced in the aromatherapy group for nulliparae (first time delivery of a child). There were no associated adverse effects of using EO's on maternal or neonatal outcomes.

Burns, E., Blamey, C., Ersser, S. J., Barnetson, L., & Lloyd, A. (2000). An investigation into the use of aromatherapy in intrapartum midwifery Practice. The Journal of Alternative and Complementary Medicine, 6(2), 141-7.

The maternal comfort of 8,058 mothers who presented in labor at the Oxford Radcliffe Hospital Women's Center between 1990 and 1998 were evaluated after being offered aromatherapy compared with those in a comparison group from the unit audit not given aromatherapy (n=15,799). The results indicate that aromatherapy offered a potentially effective therapy during labor to relieve anxiety, pain, nausea, or poor contractions.

Gedney, J., Glover, T., Fillingim, R. (2004). Sensory and affective pain discrimination after inhalation of essential oils. Psychosomatic Medicine, 66(4), 599-606.

A sex-balanced (13 men and 13 women) randomized crossover design demonstrated that inhalation of essential oil of lavender and rosemary does not produce a detectable analgesic effect. However, subjects  retrospective evaluations of aroma-induced changes in pain intensity suggest that they perceive some benefit of the intervention, especially for lavender. These findings suggest that aromatherapy may not elicit a direct analgesic effect but instead may alter affective appraisal of the experience.

Ghelardini, C., Galeotti, N., Salvatore, G., & Mazzanti, G. (1999). Local anaesthetic activity of the essential oil of lavandula augustifolia. Planta Medica, 65, 700-3.

The study compared the local anaesthetic activity of the essential oils obtained from Lavandula angustifolia and two citrus fruits. The essential oils of L. angustifolia and its two major pure components, but not the oils of Citrus reticulata and Citrus limon, were found to be able to greatly reduce the electrically evoked contractions of a rat s diaphragm in a dose-dependent manner.

Gobel, H., Schmidt, G., Soyka, D. (1994). Effect of peppermint and eucalyptus oil preparations on neurophysiological and experimental algesimetric headache parameters. Cephalalgia, 14, 228-34.

Thirty-two healthy males were included in a double-blind, placebo-controlled, randomized study with a cross-over design. The study found that the combination of peppermint oil, eucalyptus oil, and ethanol had significant muscle and mental relaxing effects, which increased cognitive performance. However, little influence on pain sensitivity was indicated.

Han, S., Hur M., Buckle, J., Choi, J., Lee, M. (2006). Effect of aromatherapy on symptoms of dysmenorrheal in college students: A randomized placebo-controlled clinical trial. The Journal of Alternative and Complentary Medicine, Jul-Aug, 12(6), 535-41.

This study of 67 female college students suggests that aromatherapy using topically applied lavender, clary sage, and rose is effective in decreasing the severity of menstrual cramps and can be offered to women experiencing menstrual cramps or painful periods. The study consisted of a double-blind, three-group experimental pre-test/post-test design, and the results indicated that menstrual cramps were significantly lowered in the aromatherapy group than in the other two groups after the post-tests.

Kim, J. et al. (2006). Evaluation of aromatherapy in treating post-operative pain: pilot study. Pain Practice, 6(4), 273-277.

The results of studies evaluating aromatherapy in treating post-operative breast biopsy pain indicated that lavender essential oil did not significantly affect pain scores; however, patients reported significantly higher satisfaction with pain control. (Kim et al, 2006).

Pittler, M. H., Ernst, E. (1998). Peppermint oil for irritable bowel syndrome: a critical review and metaanalysis. The American Journal of Gastroenterology, 93(7), 1131-5.

The results of a meta-anlysis of five double-blind, placebo-controlled, randomized controlled trials indicate that peppermint oil had a significant effect in improving symptoms of patients with irritable bowel syndrome (IBS). However, due to the methodological flaws of most of the studies, conclusions about the role of peppermint oil in the symptomatic treatment of IBS could not be drawn.

Srivasta, K. C., Mustafa, T. (1992). Ginger (Zingiber officinale) in Rheumatism and Musculoskeletal Disorders. Medical Hypotheses, 39, 342-8.

The questionnaire-based open-trial involving 56 patients evaluated the effects of ginger in rheumatoid arthritis, osteoarthritis, and muscular discomfort. More than 75% of the arthritis patients experienced relief in pain and swelling to varying degrees, and all the patients with muscular discomfort experienced relief in pain. Ginger s positive effects could be due to inhibition of prostaglandin and leukotriene biosyntheis.

Psychological Effects

Alexandrovich, I., Rakovitskaya, O., Kolmo, E., Sidorova, T., Shushunov, S. (2003). The effect of fennel (Foeniculum Volgare) seed oil emulsion in infantile colic: a randomized, placebo-controlled study. Alternative Therapies in Health and Medicine, 9(4), 58-61.

This double-blind, randomized, placebo-controlled trial evaluated the effectiveness of fennel seed oil emulsion in infantile colic. The results showed that the colic of 65% of the infants in the treatment group was eliminated compared with 23.7% in the control group; this difference was considered statistically significant. The study indicates that fennel seed oil emulsion is superior to placebo in decreasing intensity of infantile colic.

Ballard, C.G., O Brien, J.T., Reichelt, K., Perry, E.K. (2002). 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. Journal of Clinical Psychiatry, 63, 553- 8.

Ballard et al. (2002) conducted the first double-blind, randomized, placebo-controlled study to evaluate the efficacy of aromatherapy for the treatment of behavioral and psychological symptoms in dementia (BPSD). Seventy-one patients completed the trial. Patients who received aromatherapy experienced significant improvement in agitation and quality of life compared with the control group.

Cooke, B., Ernst, E. (2000). Review: aromatherapy massage is associated with small, transient reductions in anxiety. British Journal of General Practice, Jan, 50, 493-6.

Question: Does aromatherapy have an effect on clinical outcomes in patients with various conditions? Twelve studies were identified, and five studies reported that patients who received aromatherapy massage had reductions in anxiety or improvements in well-being immediately after the intervention. Five of the studies found a benefit of aromatherapy versus placebo or control. Conclusions are that aromatherapy has a small, transient effect on the reduction of anxiety immediately after administration. Individual studies suggest possible benefits of inhaled or oral aromatherapy for various conditions.

Dunn, C., Sleep, J., Collett, D. (1994). Sensing an improvement: an experimental study to evaluate the use of aromatherapy, massage and periods of rest in an intensive care unit. Journal of Advanced Nursing, 21, 34-40.

The experimental study randomly allocated 122 patients into groups to receive either massage, aromatherapy using lavender essential oil, or a period of rest. The assessment from 93 patients found no statistically significant differences in the physiological stress indicators or observed or reported behavior of patients  ability to cope following any of the three interventions. However, the patients in the aromatherapy group reported significantly greater improvement in their mood and perceived levels of anxiety than those in the other two groups.

Buckle, J. (2007). Literature review: should nursing take aromatherapy more seriously? British Journal of Nursing, 16, (2), 116-120.

This article discusses the expansion of aromatherapy within the U.S. and follows 10 years of developing protocol and policies that led to pilot studies on radiation burns, chemo-induced nausea, slow-healing wounds, Alzheimers and end-of-life agitation. This article outlines pilot studies, carried out in the U.S. by nurses, that subsequently led to the integration of aromatherapy in hospitals.

Burt, S. A. (2003). Antibacterial activity of selected plant essential oils against Escherichia coli O157:H7. Letters in Applied Microbiology 36, 162-7.

The research studied the antibacterial properties of five essential oils (EO) on Escherichia coli O157:H7. The results show that oregano and thyme EO have significant in vitro colicidal and colistatic properties and are exhibited in a broad temperature range. The effects were greatly improved by the addition of agar as stabilizer. Bay and clove bud EO are shown less active in reducing the number of E.coli O157:H7.

Dryden, M., Dailly, S., Crouch, M. (2004). A randomized, controlled trial of tea tree topical preparations versus a standard topical regimen for the clearance of MRSA colonization. Journal of Hospital Infec, 56, (4), 283-6.

A randomized, controlled study of 224 patients found tea tree to more effective at clearing MRSA from the skin of 114 hospital patients than mupirocin (Bactroban). Tea tree oil may be considered in regimens for eradication of methicillin-resistant Staaphylococcus in hospitals.

Edris, A. (2007). Pharmaceutical and therapeutic potentials of essential oils and their individual volatile constituents: A review. Phytotherapy Research 21, 308-323.

Essential oils are widely used to prevent and treat human disease. This article outlines their possible roles, which include antibacterial, antiviral, antioxidant and antidiabetic agents, as well as their potential modes of action, including prevention and treatment of cancer and cardiovascular diseases (including atherosclerosis and thrombosis). It also discusses essential

Hadfield, N. (2001). The role of aromatherapy massage in reducing anxiety in patients with malignant brain tumors. International Journal of Palliative Nursing, 7, (6), 279-285.

Eight patients were recruited to the study, which was comprised of three methods of data collection: the measurement of physical parameters, the completion of Hospital Anxiety and Depression Scales (HADS), and semi-structured interviews. The results from the HADS did not show any psychological benefit from aromatherapy massage (AM). However, there was a statistically significant reduction in all four physical parameters, which suggests that AM affects the autonomic nervous system, inducing relaxation. This finding was supported by patients during the interviews stating they felt relaxed  after AM.

Hansen, T., Hansen, B., Ringdal, G. (2006). Does aromatherapy massage reduce job-related stress? Results from a randomized, controlled trial. International Journal of Aromatherapy, June, 16, (2), 89-94.

The aim of this randomized controlled trial of 18 nurses was to test whether aromatherapy massage has a positive effect on job-related stress. The effect of the treatment was measured by Cooper s Job Stress Questionnaire. The results from the study show a positive effect on a statistically significant level of aromatherapy massage in reducing work-related stress. Due to the selective and small sample size, further research is need to draw stronger clinical implications.

Itai, T., Amayasu, H., Kuribayashi, M., Kawamura, N., Okada, M., Momose, A., Tateyama, T., Narumi, K., Waka, Kaneko, U.S. (2000). Psychological effects of aromatherapy on chronic hemodialysis patients. Psychiatry and Clinical Neurosciences, 54, 393-7.

Fourteen female inpatients with chronic renal failure were selected to participate in the study to evaluate the psychological effects of aromatherapy. Natural hospital smells and odorless conditions were systematically used as control periods. It was found that hiba oil aroma significantly decreased the mean scores of the Hamilton rating scale for depression (HAMD) and lavender aroma significantly decreased the mean scores of the Hamilton rating scale for anxiety (HAMA). There is no significant difference in the mean scores between those in an odorless condition and those in the control conditions.

Lemon, K. (2004). An assessment of treating depression and anxiety with aromatherapy. The International Journal of Aromatherapy, 14, 63-69.

Thirty-two subjects suffering from depression and/or anxiety were recruited from both inpatient and outpatient clinics of a hospital. Essential oils were selected according to physical and psychological symptoms, (e.g. anxiety, depression, headaches, and sleep problems). The test group showed a marked improvement compared to the control group. This study has statistically proven that the holistic use of aromatherapy had beneficial effect on clients who were more than mildly depressed or anxious.

Lis-Balchin, M., Hart, S. (1997). A preliminary study of the effect of essential oils on skeletal and smooth muscle in vitro. Journal of Ethnopharmacology, 58, 183-7.

This study examined the pharmacological activity of nine commercial essential oils. The results indicate that certain essential oils (clary sage, dill, fennel, frankinsense, and nutmeg) produced a contracture and inhibition of the twitch response to nerve stimulation on skeletal muscle; thyme had a contracture without a change in the twitch response; lavender reduced the twitch response alone; and camphor increased the size of the twitch response. The findings supported previous work in showing that essential oils have selective actions on biological tissues, and the actions were not non-specific toxic actions on cell membranes.

Lucks, B.C., Sorensen, J., Veal, L. (2002). Vitex agnus-castus essential oil and menopausal balance: a self-care survey. Complementary Therapies in Nursing and Midwifery, 8, 148-54.

The authors surveyed 33 women who were in the peri-menopausal to post-menopausal transition and volunteered to participate the study. The returned three-page questionnaires from 23 women indicated that the use of Vitex essential oil (both leaf and berry) helped the majority of respondents relieve their menopausal symptoms to a sufficient degree. The leaf essential oil appears to have a broader range of actions, including addressing psychological aspects.

Nguyen, Q., Paton C. (2008). The use of aromatherapy to treat behavioral problems in dementia. International Journal of Geriatric Psychiatry, 23, 337-346.

Aromatherapy is an option that has been recommended for use in dementia. This review article summarizes 11 prospective randomized studies of aromatherapy use in behavioral and psychological symptoms in dementia (BPSD). They conclude that aromatherapy is a potentially useful treatment for BPSN, and recommend that this subject be studied further to understand the use of oil, optimum method of administration, efficacy, and potential side effects.

O'Brien M.E. (1999). Aromatherapy: a definite mood booster... commentary on Schiffman S.S., Sattely-Miller E.A., Suggs M.S. et al. (1995). The effect of pleasant odors and hormone status on mood of women at midlife. Brain Research Bulletin, 36, 19-29. Complementary Medicine for the Physician, 4(4), 26-7.

Two placebo-controlled studies were conducted to evaluate 56 women and 60 men in their middle-age in the Department of Psychiatry at the Duke University Medical Center. It was found that tension, depression, confusion, and mood disturbance were significantly alleviated in the presence of pleasant odors, with no effect on physiologic symptoms of menopause for women. For men, fragrance scores were also significantly better than with placebo for all six mood factors and mood disturbances. The findings suggested that the use of pleasing odors has potential therapeutic effects in coping with midlife.

Wilkinson, S., Aldridge, J., Salmon, I., Cain, E., & Wilson. B. (1999). An evaluation of aromatherapy massage in palliative care. Palliative Medicine, 13, 409-17.

Wilkinson et al. (1999) studied 103 patients to assess the effects of massage and aromatherapy massage on cancer patients in a palliative care setting. The authors found that patients with massage had a statistically significant reduction in anxiety. Massage with essential oils improve the outcome measurement of physical and psychological symptoms and overall quality of life.

Toxicity and sensitivity

Bhushan, M., & Beck, M. (1997). Allergic contact dermatitis from tea tree oil in a wart paint. Contact Dermatitis, 36, 117-118.

This case report was about a 74-year-old man who developed allergic contact dermatitis due to the application of tea tree oil in a wart paint. It calls for attention to the presence of tea tree oil in a variety of "over-the-counter" medications.

Brandao, F. M. (1986). Occupational allergy to lavender oil. Contact Dermatitis, 249-50.

In this case report, lavender oil contained in one of the shampoos was found to be the cause for the irritant dermatitis developed on the hands and fingers of a hair-dresser.

Clark, S. M., & Wilkinson, S. M. (1998). Phototoxic contact dermatitis from 5- methoxypsoralen in aromatherapy oil. Contact Dermatitis, 38, 289-290.

In their article, Clark and Wilkinson (1998) reported a case of phototoxic contract dermatitis from exposing to 5-methoxypsoralen (5-MOP) in aromatherapy oil and discussed the mechanisms of the development of the contact dermatitis. The intravascular permeability or polymorphonuclear accumulation of the skin is increased two hours after the skin is sensitized by 8-MOP and exposed to 395-nm UVA.

De Groot, A.C., & Weyland, W. (1992). Systemic contact dermatitis from tea tree oil. Contact Dermatitis, 27, 279-80.

The case report documented an allergy incidence of tea tree oil. The atopic dermatitis of a patient became worse after being treated with undiluted tea tree oil. The actual allergen was later identified as eucalyptol, which is the most common ingredient of essential oils.

Henley, D., Lipson, N., Korach, K., Bloch, C. (2007). Prepubertal gynecomastia linked to lavender and tea tree oils. The New England Journal of Medicine, Feb 1, 356, (5), 479-485.

This study investigated causes of gynecomastia (abnormally large breast in a male) in three pre- pubertal boys who were otherwise healthy and had normal blood levels of endogenous steroids. The gynecomastia coincided with the topical application of products that contain lavender and tea tree and resolved after they were discontinued. Cell cultures suggested a hormonal effect from lavender and tea tree oils. The authors conclude that repeated topical exposure to lavender and tea tree cause the pre-pubertal gynecomastia.

Summary of editorial responses June 14 edition of NEJM: The evidence in the three case studies does not support the conclusion. The three case studies involved commercial products that contained many ingredients stored in plastic containers known to have endocrine-disrupting effects, and the study was uncontrolled with hundreds of other suspect agents possibly having a role. Traditional use and clinical trials have not suggested estrogenic effects of tea tree or lavender oil. A growing number of estrogen disrupters in our environment have been shown to accumulate in adipose tissue. Additionally, the source of the essential oils and possible oxidation were not addressed. The data does suggest a need for further studies given the widespread use of both oils.

Sugiura, M., Hayakawa, R., Kato, T., Sugiura, K., & Hashimoto, R. (2000). Results of patch testing with lavender oil in Japan. Contact Dermatitis, 43, 157-160.

The study reported the annual results of patch testing with lavender oil from 1990 to 1998 in Japan. Comparing with the positivity rates of nine other fragrances that remained stable during the nine-year period, the positivity rate of lavender oil on patch testing jumped in 1997 and 1998. This was explained to be due to the increased popularity in using dried lavender flowers in Japan.

Other interesting studies

Al-Hader, A.A., Hasan, Z.A., Aqel, M.B. (1994). Hyperglycemic and insulin release inhibitory effects of rosmarinus officinalis. Journal of Ethnopharmacology, 43, 217,22.

Al-Hader et al (1994) evaluated the effects of the volatile oil extracted from the leaves of Rosmarinus officinalis on glucose and insulin levels in normal rabbits. The results show that the intramuscular administration of the volatile oil increased the levels of plasma glucose and decreased the levels of serum insulin significantly compared with the control animals. It suggested that the volatile oil of R. offcinalis increases glucose levels in the bloodstream and inhibits the release of insulin in rabbits.

Anderson, L., Gross, J. (2004). Aromatherapy with peppermint, isopropyl alcohol, or placebo is equally effective in relieving postoperative nausea. Journal of Peri-Anesthesia Nursing, 19, (1), 29-35.

Investigators studied 33 male and female patients at an outpatient surgery facility who complained of nausea in the recovery room. After indicating the severity of the nausea on a visual analogue scale subjects received aromatherapy with isopropyl alcohol, oil of peppermint, or saline (placebo). The results of this study indicate that initial treatment of postoperative nausea with aromatherapy reduces patients' subjective perception of nausea and IV antiemetic use in the recovery room by nearly 50%. Despite the small sample size, this effect had a high degree of statistical significance.

Dwivedi, C. & Zhang, Y. (1999). Sandalwood oil prevents skin tumour development in CD1 mice. European Journal of Cancer Prevention, 8, 449-55.

This laboratory research investigated the chemopreventive effects of sandalwood oil (SW oil) on CD1 mice. The results suggested that SW oil treatment (100ul, 5% in acetone, twice a week, topically) significantly decreased papilloma incidence by 67% and multiplicity by 96% in a concentration and time-dependent manner in the studied mice. It was suggested that SW oil may be useful to prevent chemically induced skin cancer.

Hay, I.C., Jamieson, M., Ormerod, A. D. (1998). Randomized Trial of Aromatherapy. Archives of Dermatology, 134, 1349-52.

This randomized, double-blind, controlled trial assessed the efficacy of essential oils (thyme, rosemary, lavender, and cedarwood) in the treatment of 86 patients with baldness. There were significantly more patients in the treatment group (19/43) who showed improvement than that in the control group (6/41). It was shown that aromatherapy was significantly more effective than treatment with the carrier oil alone in treating baldness.

Oyedele, A. O., Gbolade, A. A., Sosan, M.B., Adewoyin, F. B., Soyelu, O.L., & Orafidiya, O. O. (2002). Formulation of an effective mosquito-repellent topical product from Lemongrass oil. Phytomedicine, 9, 259-62.

The study tested the mosquito repellency of six different formulations of lemongrass oil in different classes of base and the oil in liquid paraffin solution. The repellency exhibited by the 1% v/v solution and 15% v/w cream and ointment preparations of the lemongrass oil was comparable to that of a commercial mosquito repellent.

Rose, J. E. & Behm, F. M. (1994). Inhalation of vapor from black pepper extract reduced smoking withdrawal symptoms. Drug and Alcohol Dependence, 34, 225-9.

Forty-eight cigarette smokers were randomly assigned to one of the three groups after overnight deprivation from smoking. Participants who puffed and inhaled a vapor from essential oil of black pepper reported significantly less cravings for cigarettes than those in the other two control groups who puffed on the device with a mint/menthol or an empty cartridge. Those in the essential oil group also reported less negative effects and physical symptoms of anxiety.

Saeki, Y. (2000). The effect of foot bath with or without the essential oil of lavender on the autonomic nervous system: a randomized trial. Complementary Therapies in Medicine, 8, 2- 7.

The use of Lavandula augustifolia at a 0.05% dilution gives a weak relaxation response, as well as increased peripheral circulation, demonstrated through several changes in cardiovascular parameters.

Literature Reviews

Buckle, J. (2007). Literature review: should nursing take aromatherapy more seriously? British Journal of Nursing, 16, (2), 116-120.

This article discusses the expansion of aromatherapy within the U.S. and follows 10 years of developing protocol and policies that led to pilot studies on radiation burns, chemo-induced nausea, slow-healing wounds, Alzheimers and end-of-life agitation. This article outlines pilot studies, carried out in the U.S. by nurses, that subsequently led to the integration of aromatherapy in hospitals.

Edris, A. (2007). Pharmaceutical and therapeutic potentials of essential oils and their individual volatile constituents: A review. Phytotherapy Research 21, 308-323.

Essential oils are widely used to prevent and treat human disease. This article outlines their possible roles, which include antibacterial, antiviral, antioxidant and antidiabetic agents, as well as their potential modes of action, including prevention and treatment of cancer and cardiovascular diseases (including atherosclerosis and thrombosis). It also discusses essential oils' application as natural skin penetration enhancers for transdermal drug delivery and their therapeutic properties with regard to aroma and massage therapy.

Halm, M. (2008). Essential oils for management of symptoms in critically ill patients. American Journal of Critical Care, 17, (2), 160-163.

This clinical review summarizes current evidence related to the following question: How effective are essential oils in management of symptoms in critically ill patients? Five studies, one systematic review, one literature review, and one ICU case report were examined. Research into the therapeutic effects of essential oils is recommended for further scientific investigation so the legitimacy of the interventions can be further assessed.

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