Essential Oils - Research

Aromatherapy is the practice of using aromatic oils and scented botanical mixtures to treat a variety of disorders.

Research studies on the use of essential oils in aromatherapy show positive effects for a variety of health concerns including pain, anxiety, depression, agitation, premenstrual syndrome, nausea, and more.  For example, peppermint has been used to relieve nausea while orange and lavender have been used to reduce anxiety and boost people’s moods.

From #1 Below) “Although essential oils have been used therapeutically for centuries, there is little published research on many of them.  However, this is beginning to change as more scientific studies on essential oils are conducted around the world.  Clinical studies are currently underway in Europe, Australia, Japan, India, the United States, and Canada. Many of these studies describe the remarkable healing properties of various oils.”

·         Much of the research on essential oils is being conducted by food, flavoring, cosmetics, and tobacco industries.  These industries are interested in learning more about essential oils in regards to flavorings, preservative qualities, and mood altering.

·         It can be difficult to research essential oils for several reasons.  1) They are not standardized. Unlike a synthetic (lab-created) product, essential oils come from plants and will vary in how much of varying chemicals they contain based on local conditions such as soil, weather, and insect predation. 2) It is hard to conduct double blind studies on aromatherapy oils because they have strong fragrances—which can be recognized by participants. 3) Drug studies are expensive. Traditional drug studies are funded by pharmaceutical companies—and there is little motivation for them to test essential oils because these are not patentable products.

 Research based findings…

It is important to note that other studies have found no difference between outcomes in people treated with essential oils and those treated with a placebo. For example, aromatherapy with peppermint was equally effective as alcohol or a placebo in relieving postoperative nausea (Anderson and Gross 2004), and no differences were observed between

From Alexandrovich (2003)

·         In a clinical study of 125 infants, fennel seed oil was shown to significantly improve colic. Study suggests that fennel seed oil is superior to placebo in decreasing intensity of colic. Infants received a water emulsion of 0.1% fennel seed oil.

·         Parents gave 5-20ml of fennel seed oil emulsion up to 4 times a day, orally before meals or at the onset of colic episodes

·         “There was no significant difference in cumulative crying between the 2 groups prior to the trial, but there was a significant decrease in cumulative crying in infants in the treatment group.”

·         Use of Fennel Seed Oil eliminated colic in 65% of infants in the treatment group (sig better than 23.7% of infants in the control group)

·         Postulated mechanism in the pathogenesis of colic may be a spasm of the intestinal smooth muscle. The therapeutic effect of fennel seed oil may be to reduce this smasming.

#3 Ballard et al 2002—No differences observed in releiveing postoperative nausea between peppermint, isopropyl alcohol, and a placebo. “The fact that a saline “placebo” was as effective as alcohol or peppermint suggests that the beneficial effect may be related more to controlled breathing patterns than to the actual aroma inhaled.”

#4 Below –not a lot of details on what oils were used (could be lavender, mandarin, roman chamomile, Frakincense, and/or clary sage and could have been administered in many different ways. .  Generally, no differences were found in any of their outcomes except that fewer babes needed to go to the NICU in the control group.

#5 below (Chang 2008). This study examined the effects of hand massage with essential oils on pain, anxiety, and depression in hospice patients with terminal cancer. All patients received either a 5 minute hand massage on each side for seven days, or the same massage with Bergamot, Lavender, and Frankincense (1:1:1) essential oils.  The aroma hand massage experimental group showed significantly less pain and depression than the control group.

#6 below (Gedney et al 2004). This study examined the effects of breathing essential oils on pain. Subjects inhaled either essential oil of lavender, rosemary or distilled water. They reported pain intensity and pain unpleasantness on a visual analog scale. No differences were observed between treatments during the pain. However, retrospectively, the pain seemed less unpleasant in those treated with lavender and marginally so in those treated with rosemary, compared with the control condition.

#7 below (Han et al 2006). This randomized placebo-controlled  study explored the effects of aromatherapy on menstrual cramps.  Participants in the trail were 67 college students who scored their menstrual cramps as greater than six on a ten point scale but had no underlying disease.  One third of these students were a control group with no intervention.  One third were a placebo group who had abdominal massage with almond oil.  One third were the experimental group who had aromatherapy applied during the abdominal massage: these had the same almond oil plus two drops of lavender, one drop of clary sage, and one drop of rose essential oils. Participants rated their menstrual cramps again on day one and two of menstruation after treatment. The aromatherapy treatment had significant changes in menstrual cramp levels. “The experimental group received aromatherapy every day beginning one week before the start of menstruation and continuing until the first day of menstruation. The experimental and placebo groups received 15 min of aromatherapy or placebo, respectively. Each treatment lasted about fifteen minutes.

#8 below (Haze et al 2002). This study examined the effects of inhaling essential oils on sympathetic activity in normal adults using both blood pressure fluctuations and measurement of plasma catecholamine levels. Common catecholamines in the human body include adrenaline, noradrenaline, and dopamine. Adrenaline and noradrenaline are released as part of the fight or flight response while dopamine is a neurotransmitter. “Previous research has shown that some fragrances exert stimulant or relaxant effects on brain function.  Moreover, it has been reported that human endocrine and immune systems are affected by fragrance in a study that examined effects of fragrance on endocrine function (urinary cortisol and dompamine levels) and immune function (natural killer cell activity and CD4/8 values; Komori 1995, citrus fragrance immune function).  Also see Heuberger et al 2001 Effects of chiral fragrances…”  Forty three healthy females between 22 and 25 were examined in this study using six essential oils: peper, grapefruit, estragon (tarragon), fennel, patchouili (a member of the mint family) and rose oil. These essential oils are widely used in fragrance, cosmetic, and food industries. Subjects inhaled either the essential oil dissolved in triethyl citrate (an odorless solvent), or the TEC itself, for 3min or 7 min. After resting for 30 minutes, the blood pressure was taken. In a separate study, participants had blood samples taken and tested for adrenaline, noradrenaline, and dopamine before and after inhaling these compounds. Fragrance inhalation of pepper oil, estragon oil, fennel oil, or grapefruit oil induced a significant 1.7 to 2.5 fold increase in relative sympathetic activity. In contrast, inhalation of rose or patchouli oil resulted in approximately 40% decrease in relative sympathetic activity (BLOOD PRESSURE, Heart rate). Additionally, fragrance inhalation of pepper oil showed a 1.7 fold incrase in plasma adrenaline concentratin (P = 0.06). In contrast, fragrance inhalation of rose oil resulted in a 30% decrease in adrenaline concentration.

Interesting note about this article is that Haze works for the Product Development Center for the company Shiseido—a japanese skincare, makeup, and fragrance company.  (

#9 below  Itai et al. 2000. Small study (14 female patients) on effects of inhaling lavender or Hiba (conifer in the cypress family, endemic to Japan) essential oils on mood in chronic hemodialysis patients.  Suggests that HIBA oil reduces both depression and anxiety, and lavender oil reduces anxiety.

#10 below Kane et al 2004. Small study (8 patients) on effects of lavender /lemon essential oils  (as “odours”) on pain upon dressing changes. These did not reduce pain intesnsity during the dressing change but there was a sig reduction in pain intensity for the lavender therapy after the dressing change.

#11 below Kim et al 2006. Small study (50 patients) using lavender oil aromatherapy in a supplemental oxygen face mask (or no lavender control) to examine postoperative pain. No significant differences in narcotic requirements or pain scores. However, patients in the lavender group reported a higher satisfaction rate with pain control than patients in the control group (P = 0.0001).

#12 below Lehrner et al 2005. 200 dental patients in one of four groups: ambient odor of orange or lavender essential oil, music, or control (no music, no odor). Both ambient odors of orange and lavender reduced anxiety and improved mood in patients waiting for dental treatment.  “These findings support previous work suggesting that odors are capable of altering emotional states and may indicate that the use of odors is helpful in reducing anxiety in dental patients.”

#13 below Lemon et al. 2004. Thirty two subjects suffering from depression or anxiety. Aromatherapy was given via massage.  All participants received six 40 min massages, half with essential oils selected based on symptoms and half (control) with no essential oils. Significant differences between aromatherapy and control groups, with test group showing marked improvement in depression and anxiety symptoms.

#14 below Nguyen and Patton. 2008. Review article on the use of aromatherapy to treat behavioral problems in dementia. “Data supporting the efficacy of aromatherapy are scarce; available studies reported positive and negative consequences for both people with dementia and their care-givers.” 

#15 below Snow et al. 2004. Study examining whether inhaled aromatherapy affects  agitation in dementia patients. No evidence that purely olfactory forms of aromatherapy decrease agitation in severely demented patients. Significant evidence in literature that people with dementia have impaired olfactory abilities. Evidence in previous papers suggest cutaneous application of the essential oil via massage may be necessary to achieve reductions in dementia previously reported.


2)       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.

3)       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.

4)       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.

5)       Chang, SY. (2008). Effects of aroma hand massage on pain, state anxiety and depression in hospice patients with terminal cancer. Daehan Ganho Haghoeji, 38(4), 493-502.

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

7)       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.

8)       Haze, S, Sakai, K & Gozu, Y. (2002). Effects of fragrance inhalation on sympathetic activity in normal adults. Japanese Journal of Pharmacology, 90, 247-253.

9)       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.

10)   Kane, FM, Brodie, EE, Couli, A, et al. (2004). The analgesic effect of odour and music upon dressing change. British Journal of Nursing, 13(19), S4-12.

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

12)   Lehrner, J., Marwinski, G., Lehr, S., Johren, P., & Deecke, L. (2005). Ambient odors of orange and lavender reduce anxiety and improve mood in a dental office. Physiology & Behavior, 86(1-2), 92-95.

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

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

15)   Snow L, Hovanec L & Brandt J. (2004). A controlled trial of aromatherapy for agitation in nursing home patients with dementia. J Alternative & Complementary Medicine, 10 (3), 431-437.