- Aromatherapy involves the controlled use of aromatic essential plant oils.
- Weak evidence is available to indicate that aromatherapy can improve overall quality of life; may be of potential benefit for physical problems (pain or fatigue), psychological problems (anxiety, depression, sleep).
- There is no strong evidence for long-term aromatherapy effects (after several weeks).
- Aromatherapy is generally safe; the greatest risks involve the consumption of larger amounts of essential oil or the application of essential oils to the skin, which may cause allergic contact dermatitis.
Aromatherapy, also called essential or volatile oil therapy, entails the controlled use of essential oils that have been extracted from a variety of plant sources. Therapy is usually given via massage, inhalation or a foot- or full-body bath.
Claims of benefits for cancer patients include reduced anxiety levels and relief of emotional stress, pain, muscular tension and fatigue. Claims for the effect of certain oils range from ‘restoring harmony to the energy’ of the body, altering mood and improving overall health, to more specific claims such as having anticonvulsive and spasmolytic properties.
The latest Cochrane review (2016) evaluated massage with or without aromatherapy for symptom relief in people with cancer. This systematic review presented evidence from six studies comparing aromatherapy massage with no massage and two studies comparing aromatherapy massage and massage without aromatherapy. The review concludes that there is limited evidence that aromatherapy may be useful for people with cancer in terms of relief from pain and anxiety, this was due to methodological limitations of studies. Evidence from an additional 13 randomised clinical trials of varying methodological quality is contradictory; more consistent research is needed to assess the long-term effects of aromatherapy for people with cancer.
Although essential oils have generally shown minimal adverse effects, when used in appropriate dilutions, allergic reactions can occur with all oils. Repeated topical administration of lavender and tea tree oil has been associated with reversible prepubertal gynecomastia, consequently there may be issues for cancer patients with oestrogen-dependant tumours.
Summary fully revised and updated in May 2017 by Helen Seers.
Summary fully revised and updated in December 2015 by Helen Seers.
Last updated in September 2013 by Katja Boehm.
Summary fully revised and updated in June 2012 by Katja Boehm.
Summary first published in March 2011, authored by Katja Boehm and Thomas Ostermann.
Helen Seers, Katja Boehm, CAM-Cancer Consortium. Aromatherapy [online document]. May 20, 2017.
Aromatherapy encompasses the controlled use of aromatic essential oils derived from many different types of plants (more often the uncrushed whole plant) claimed to possess therapeutic properties within a variety of application methods. Aromatherapy is also referred to as essential or volatile oil therapy or, more rarely, aromatic medicine.
Approximately 40 different essential oils extracted from various plants are used in aromatherapy, processed either through distillation or cold pressing (expression). Lavender, rosemary, eucalyptus, chamomile, marjoram, jasmine, peppermint, lemon, ylang ylang and geranium are some of the most popular plants used1,33.
Application and dosage
Aromatherapy/essential oils can either be self-administered or administered by a practitioner. An aromatherapy massage typically lasts between 60 and 90 minutes. Many aromatherapists are primarily trained as massage therapists and use essential oils as part of their practice. Most commonly diluted oils are applied topically, often together with a carrier oil, as part of massage therapy to manipulate soft body tissue, or else by inhalation of the aroma using an incense burner or via ‘aromasticks’. In addition, some essential oils are ingested as teas, added to bathwater or pillows, or added to ointments, creams and compresses. It has been suggested that a safe and effective maximum dilution for most aromatherapy/essential oils in massage therapy is 2.5% for adults (2 drops of essential oil per 100 drops of carrier oil) and 5–10 drops for full-body baths.
Aromatic, perfumed oils were used in ancient Egypt to embalm mummies, as well as in ancient China and India. The Persian philosopher and scientist Avicenna (c. AD 980–1037) was the first to distil oil from the rose plant2. The term ‘aromatherapy’ was coined by French chemist and perfumiér René Maurice Gattefossé in his 1937 bookAromathérapie: Les Huiles essentielles hormones végétales as a subcategory of ‘herbal medicine’.
Gattefossé suggested aromatherapy could be used to treat diseases in virtually every organ system, citing mostly anecdotal and case-based evidence3. Other notable aromatherapists who helped lay the foundation for modern practice are Dr Jean Valnet, who used aromatherapy to treat soldiers during WWII; Madame Marguerite Maury, an Austrian biochemist who brought aromatherapy into the world of cosmetics and developed their use in massage; and Robert B. Tisserand, an English Aromatherapist recognized for bringing aromatherapy to English speaking populations3. In the 1980s aromatherapy increased in popularity in the USA.
Today aromatherapy is fairly well-established in countries such as Australia, Canada, France, Germany, New Zealand, Switzerland and the UK4. Professional aromatherapists, nurses, physical therapists, pharmacists and massage therapists can all provide topical or inhalation aromatherapy treatment5.
Claims of efficacy and alleged indications
Essential oils are used to improve physical, spiritual and emotional wellbeing. A wide range of claims have been made for the effect of certain oils, ranging from affecting the ‘subtle body’ of a patient to having anticonvulsive and spasmolytic properties. It has been suggested that the topical application of aromatic oils may exert antibacterial, anti-inflammatory and analgesic effects. For cancer patients, claims of benefits include reduced anxiety levels and relief from emotional stress, pain, muscular tension and fatigue. Some of these alleged outcomes have been vaguely defined.
It has been claimed that the application of aromatherapy can help patients with stress, chronic pain, nausea and depression; in addition they may contribute towards the relief of bacterial infections, stimulation of the immune system; it has also been asserted that they can assist in combating colds and sore throats, increasing urine production and circulation, relieving cystitis, herpes simplex, acne, headaches, indigestion, premenstrual syndrome and muscle tension. Specific indications vary according to the oils used6. There is currently no evidence to prove any of these claims.
Mechanisms of action
The chemical properties and composition of a specific type of essential oil determines the therapeutic qualities it might have. A number of theories, which fall within the two broad categories of psychological aspects or neuro-chemical effects, try to explain the mechanisms of action. It has been suggested that effects on the limbic and olfactory system also affect mood4, but only very limited research confirms such mechanisms. Proponents of essential oils/aromatherapy also believe that the overall effects these oils have on the body are greater than the sum of the individual components of the scents7.
Prevalence of use
Aromatherapy use by cancer patients varies from country to country. A systematic review in 2011 showed, for example: 1% in Australia (three surveys); between <1 and 4% in Canada (two surveys); <1–2% in Italy, Spain and Turkey; 40.6% in the UK (six surveys); 11% in the USA, and 6% in New Zealand8.
There is no single regulatory organisation specifically for aromatherapy, but membership of a number of professional organisations is open to aromatherapists such as the International Federation of Aromatherapists, Also, legal restrictions apply in some countries because of the way in which essential oils can be administered, namely both orally and rectally; in such instances the application must be carried out by a medically qualified person.
Costs and expenditures
Some cancer clinics or other voluntary organisations now offer aromatherapy or aromatherapy massage free of charge or at a reduced cost. Treatments of aromatherapy massage usually cost between €30 and €85 for a 60 to 90 minute session 3. Aromatherapy oils can be purchased from a variety of sources, including health shops, larger supermarkets and the Internet. Prices can vary markedly.
The overall evidence for aromatherapy based on systematic reviews and randomised clinical trials provides limited evidence suggesting that aromatherapy might have positive short-term, effects on quality of life, physical and psychological problems for people with cancer. There were large variations in the type of aromatherapy used, controls and outcomes in the assessed studies. Most studies had methodological limitations.
No published studies have looked directly at aromatherapy as a cancer treatment. Instead, the literature has investigated aromatherapy’s possible effects in supportive and palliative cancer care such as quality of life and psychological/physical problems associated with cancer.
Shin et al. (2016) published a Cochrane review of massage with or without aromatherapy for symptom relief (pain, anxiety, symptoms relating to the breast, and quality of life) for people with cancer9. Six of the included studies capturing data from 561 participants compared aromatherapy massage with no massage. The quality of the evidence was judged as very low as studies were generally at a high risk of bias. Although there was some indication of benefit in the aromatherapy-massage groups, this benefit is unlikely to translate into clinically relevant benefit. Results included one RCT showing medium-term pain relief (n= 86, mean difference, MD 5.30; 95% CI 1.52 to 9.08), one RCT showing long-term pain relief (n = 86, MD 3.80; 95% CI 0.19 to 7.41); two RCTs reporting positive results for aromatherapy and anxiety (n= 253, combined MD -4.50; 95% CI -7.70 to -1.30), one RCT (n=86, MD -9.80; 95% CI -19.13 to -0.47) helping with physical breast cancer symptoms; one RCT (n = 30, MD -2.00; 95% CI -3.46 to -0.54) reporting a medium-term quality of life score was lower (better) for the aromatherapy-massage group compared with the no-massage group.
Two of the included studies (n=117) compared massage with aromatherapy and massage without aromatherapy. Results showed a lack of evidence for the clinical effectiveness of aromatherapy for the relief of pain, anxiety, depression, physical symptom distress or quality of life. Key outcomes of studies were not reported in detail due the small size of the trials. Overall, Shin et al. concluded that there was unclear clinical evidence of any benefit in terms of pain and anxiety relief, due to the methodological limitations of the evidence available9.
Chen et al. (2016) conducted a meta-analysis of RCTs to look at the clinical effectiveness of aromatherapy massage on reducing pain10. The authors identified three studies meeting their criteria for inclusion in the meta-analysis, only one of these studies was also included in the above Cochrane review by Shin et al. Chen et al.’s meta-analysis pooled data from 278 participants (135 in aromatherapy and 143 participants in control group). Aromatherapy had a nonsignificant effect on reducing pain (standardized mean difference, SMD=0.01; 95% CI −0.23, 0.24)10.
Yim et al. (2009) carried out a systematic review including six randomised and non-randomised controlled clinical trials on aromatherapy massage in patients with depression11. Three of these studies evaluated the benefit of Swedish massage (two with lavender oil) for depressive symptoms of cancer patients (mainly women with breast cancer). Results showed significant short term-improvement in anxiety and/or depression compared with usual care. According to the authors, this improvement might be explained by the induction of a relaxation response in the autonomic nervous system. Wilkinson et al.’s (2008) earlier reviews on aromatherapy arrived at similar conclusions; however, none of them deal specifically with the topic of cancer5.
Randomised controlled trials
Overall, the evidence of the above RCTs seems to confirm the findings of the systematic reviews and points to a short-term benefit of aromatherapy massage with improvement in general quality of life, potential improvement of some physical problems (pain, fatigue), psychological difficulties (anxiety, depression, sleep) and salivary gland function. It is difficult to draw overall conclusion of the evidence as the RCTs used different types of aromatherapy (n=7 relate to aromatherapy massage while n=6 relate to aromatherapy inhalation), use different controls and the findings are not consistent across all of the trials described in Table 1. It is also not possible to assess the efficacy of specific essential oils. The quality of the trials up until now has ranged from low to mediocre.
Aromatherapy is considered safe when administered by a qualified aromatherapist whose expertise includes working with the needs of people who have cancer.
Tests of essential oils for safety have shown minimal adverse effects. A number of oils have therefore been approved for use as food additives and are classified as GRAS (generally recognised as safe) by the US Food and Drug Administration. Nevertheless there is a risk involved in the consumption of essential oils25. Also, a review on the safety assessment of St John’s wort (Hypericum perforatum) oil has concluded that the available data are insufficient to support the use of ingredients from this plant as safe for use in cosmetic formulations26.
Some essential oils (e.g. camphor oil) can cause local irritation. The main concern with essential oils seems to be regarding cases of contact dermatitis, mostly reported in aromatherapists who have had prolonged skin contact with oils in the context of aromatherapy massage. Moreover, phototoxicity has been found to occur when essential oils (particularly citrus oils) are applied directly to the skin before exposure to the sun27.
Odours from essential oils may result in adverse psychological responses, especially if the memory of a particular scent evokes strong emotions (Holmes26) In addition, Hongratanaworakit et al. have reported that sweet orange oil (Citrus sinensis) can have a stimulatory effect on the cardiovascular system28.
One study has shown that repeated topical exposure to lavender and tea tree oils by topical administration was associated with reversible prepubertal gynecomastia29. Therefore, these two essential oils could cause problems in patients with oestrogen-dependant tumours.
Further contraindications, especially for people with cancer, are associated with contagious diseases, broken skin, varicose veins and circulatory disorders30. Caution is also indicated for those who are pregnant, or trying to get pregnant, breastfeeding, or have kidney disease, liver disease, asthma or epilepsy31.
Drugs that act as depressants on the central nervous system can interact adversely with aromatherapy. These drugs include narcotics such as morphine or oxycodone (OxyContin) for pain, as well as sedative and anti-anxiety agents such as lorazepam (Ativan), diazepam (Valium) and alprazolam (Xanax)32. Some aromatherapies can cause sleepiness or drowsiness.
Aromatherapy inhalation should not be used by people with asthma.
- Tisserand R, Balacs T. Essential oil safety. Edinburgh: Churchill Livingstone, 1995.
- 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.
- Gattefossé RM. Gattefossé's Aromatherapy. Edited by R Tisserand, Translated by L Davies. Saffron Waldon: The CW Daniel Company, 1993.
- Boehm K, Büssing A, Ostermann T. Aromatherapy as an adjuvant treatment in cancer care--a descriptive systematic review. Afr J Tradit Complement Altern Med 2012;9:503-18. eCollection 2012. Review.
- Wilkinson S, Barnes K, Storey L. Massage for symptom relief in patients with cancer: systematic review. J Adv Nurs 2008;63:430-9.
- Hudson R. The value of lavender for the rest and activity in the elderly patient. Complement Ther Med. 1996;4:52–7.
- Perry N, Perry E. Aromatherapy in the management of psychiatric disorders: clinical and neuropharmacological perspectives. CNS Drugs 2006;20: 257-80.
- Horneber M, Bueschel G, Dennert G, Less D, Ritter E, Zwahlen M. How many cancer patients use complementary and alternative medicine: a systematic review and metaanalysis. Integr Cancer Ther 2012;11:187-203
- Shin ES, Seo KH, Lee SH, Jang JE, Jung YM, Kim MJ, et al. Massage with or without aromatherapy for symptom relief in people with cancer. The Cochrane database of systematic reviews. 2016(6):Cd009873. Epub 06/04.
- Chen TH, Tung TH, Chen PS, Wang SH, Chao CM, Hsiung NH, et al. The Clinical Effects of Aromatherapy Massage on Reducing Pain for the Cancer Patients: Meta-Analysis of Randomized Controlled Trials. Evidence-based complementary and alternative medicine : eCAM. 2016;2016:9147974. Epub 02/18.
- Yim VW, Ng AK, Tsang HW, Leung AY. A review on the effects of aromatherapy for patients with depressive symptoms. J Altern Complement Med 2009;15:187-95.
- Chang SY. Effects of aroma hand massage on pain, state anxiety and depression in hospice patients with terminal cancer. J Korean Acad Nurs 2008;38:493-502.
- Graham PH, Browne L, Cox H, et al. Inhalation aromatherapy during radiotherapy: results of a placebo-controlled double-blind randomized trial. J Clin Oncol 2003;21: 2372-6.
- Lai TK, Cheung MC, Lo CK, Ng KL, Fung YH, Tong M, Yau CC. Effectiveness of aroma massage on advanced cancer patients with constipation: a pilot study. Complement Ther Clin Pract 2011;17:37-43.
- Lua PL, Salihah N, Mazlan N. Effects of inhaled ginger aromatherapy on chemotherapy-induced nausea and vomiting and health-related quality of life in women with breast cancer. Complement Ther Med 2015;23:396-404.
- Maddocks-Jennings W, Wilkinson JM, Cavanagh HM, Shillington D, Maddocks-Jennings W, Wilkinson JM, et al. Evaluating the effects of the essential oils Leptospermum scoparium (manuka) and Kunzea ericoides (kanuka) on radiotherapy induced mucositis: a randomized, placebo controlled feasibility study. European Journal of Oncology Nursing 2009 ;13:87-93.
- Nakayama M, Okizaki A, Takahashi K. A randomized controlled trial for the effectiveness of aromatherapy in decreasing salivary gland damage following radioactive iodine therapy for differentiated thyroid cancer. Biomed Res Int 2017;2016:9509810.
- Ndao DH, Ladas EJ, Cheng B, Sands SA, Snyder KT, Garvin JH, Kelly KM. Inhalation aromatherapy in children and adolescents undergoing stem cell infusion: results of a placebo-controlled double-blind trial. Psychooncology 2012; 21: 247–54.
- Pimenta F, Alves M, Pimenta M, Melo S, Almeida A, Leite J, et al. Anxiolytic effect of Citrus aurantium L. on patients with chronic myeloid leukemia. Phytother Res 2016;30:613-7.
- Potter P, Eisenberg S, Cain KC, Berry DL. Orange interventions for symptoms associated with dimethyl sulfoxide during stem cell reinfusions: a feasibility study. Cancer Nurs 2011;34:361-8.
- Serfaty M, Wilkinson S, Freeman C, Mannix K, King M. The ToT Study: Helping with Touch or Talk (ToT): a pilot randomised controlled trial to examine the clinical effectiveness of aromatherapy massage versus cognitive behaviour therapy for emotional distress in patients in cancer/palliative care. Psychooncology 2012;21:563-9.
- Stringer J, Swindell R, Dennis M, Stringer J, Swindell R, Dennis M. Massage in patients undergoing intensive chemotherapy reduces serum cortisol and prolactin. Psycho-Oncology 2008;17:1024-31.
- Tamaki K, Fukuyama AK, Terukina S, Kamada Y, Uehara K, Arakaki M, et al. Randomized trial of aromatherapy versus conventional care for breast cancer patients during perioperative periods. Breast Cancer Res Treat 2017;162:523-31.
- Tang WR, Chen WJ, Yu CT, Chang YC, Chen CM, Wang CH, Yang SH. Effects of acupressure on fatigue of lung cancer patients undergoing chemotherapy: an experimental pilot study. Complement Ther Med 2014;22:581-91.
- Ljunggren B. Severe phototoxic burn following celery ingestion. Arch Dermatol 1990;126:1334-6.
- Anonymous. Final report on the safety assessment of Hypericum perforatum extract and Hypericum perforatum oil. International Journal of Toxicology. 2001;20 Suppl 2:31-9.
- Clark SM, Wilkinson SM. Phototoxic contact dermatitis from 5-methoxypsoralen in aromatherapy oil. Contact Dermatitis 1998;38: 289–90.
- Hongratanaworakit T, Buchbauer G. Human behavioral and physiological reactions to inhalation of sweet orange oil. Acta Hort 2005;679:75-81.
- Henley DV, Lipson N, Korach KS, et al. Prepubertal gynecomastia linked to lavender and tea tree oils. N Engl J Med 2007; 356:479-85.
- Ernst E, Pittler MH, Wider B, Boddy K. The Oxford Handbook of Complementary Medicine. Oxford: Oxford University Press, 2008.
- Alliance of International Aromatherapists. A brief history of aromatherapists available online. Accessed May 2017.
- University of Maryland Medical Center. Lavender URL: http://www.umm.edu/health/medical/altmed/herb/lavender [online document], accessed 5th May 2017.
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