Description
Aromatherapy 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.
In cancer care, aromatherapy is primarily used as a supportive treatment to manage symptoms and adverse effects associated with cancer and its treatment, especially for anxiety, nausea, sleep and some pain. It acts mainly through olfactory/limbic modulation and specific molecular targets.
Efficacy
Eleven systematic reviews (SRs), including one Cochrane review, published in the last 10 years were assessed for this summary. There were large variations in the type of aromatherapy, controls and outcomes in the assessed studies.
Quality of the studies included is generally low, with frequent methodological limitations affecting the strength of the conclusions.
- Moderate evidence of benefit was found for reducing anxiety (6 SRs) and improving sleep (5 SRs).
- Depression (6 SRs): outcomes are less consistent, with most reviews showing no or minimal effect.
- Chemotherapy-induced nausea and vomiting (5 SRs), fatigue (5 SRs), pain (4 SRs), and quality of life (4 SRs) outcomes have contradictory evidence, as some SRs report benefits while others do not.
Safety
Topical and inhalation use of essential oils is generally considered safe when properly diluted and used appropriately. Oral ingestion of essential oils is not recommended due to risks of toxicity and adverse interactions. The safety depends on the respective essential oils used.
Description and definition
Aromatherapy involves the controlled use of essential oils derived from plants, typically through distillation or cold pressing. It utilizes essential oils extracted from various plants, including lavender, rosemary, chamomile, peppermint, and eucalyptus (Tisserand 1995; CRUK 2021). The term “aromatherapy” was coined by René-Maurice Gattefossé in 1937, advocating its role in treating multiple conditions (Gattefossé 1993).
Alleged indications
Essential oils are used to support physical and emotional wellbeing. Applications span stress, chronic pain, depression, nausea, infections, PMS, headaches, and muscular tension. For oncology patients, symptom management in supportive care including anxiety, sleep, nausea and pain (NMD 2021).
Mechanisms of action
Essential oil activity is determined by their respective chemical composition, with effects mediated through olfactory–limbic pathways, neurochemical modulation, and immune or cellular mechanisms. (Kim 2024).
Psychological and Symptom Management
Sleep: Inhalation improves quality via CNS/limbic activation and serotonin/endorphin release (Cheng 2022).
Anxiety: Massage (lavender, chamomile, mandarin, tea tree) reduces cortisol and enhances parasympathetic tone (Li 2022).
Depression: Inhalation enhances serotonin/endorphin activity (Liu 2022).
Chemotherapy-induced nausea/vomiting: Inhalation (chamomile, ginger, cardamom, peppermint) stabilizes brain waves and reduces stress-related nausea (Toniolo 2021; Ahn 2024).
Immune modulation
Reported in humans or preclinical studies with Eucalyptus globulus, Lavandula officinalis, Melaleuca alternifolia (Kim 2024), and Citrus limon (Sharma 2022).
Preclinical anticancer activities
Cytotoxicity: Abies alba, Artemisia campestris, Cedrus atlantica, Curcuma aromatica, Lippia citriodora, Calophyllum inophyllum (Sharma 2022; Kim 2024).
Apoptosis induction: Allium sativum, Boswellia sacra, Curcuma aromatica, Eupatorium adenophorum, Lavandula angustifolia, Lindera umbellata, Melissa officinalis (Kim 2024).
Anti-angiogenesis: Citrus limon, Salvia officinalis, geraniol-containing oils, lavendin, mint species, cherries, lavender, orange, citronella (Sharma 2022; Lu 2025).
Anti-mutagenic: Frankincense via modulation of phase I/II enzymes (Sharma 2022).
Antioxidant activity: Wedelia chinensis enhances antioxidant enzymes in vivo (Manjamalai 2013).
Application and provider
Essential oils are most commonly applied via inhalation or diluted topical application or added to baths, creams, and compresses. Generally, dilutions range from 0.5 to 5% dilution with a 2% essential oil dilution generally regarded as a safe guideline for dermal application on healthy adults.
A typical aromatherapy massage lasts 60–90 minutes. Inhalation methods include aromasticks or diffusers. In some cases, ingestion is practiced, but typically under medical supervision.
Legal issues
Aromatherapy is not uniformly regulated. Professional bodies (e.g., International Federation of Aromatherapists) offer accreditation. Many aromatherapists are primarily trained as massage therapists and use essential oils as part of their practice. In jurisdictions where oral or rectal administration is permitted, it must be performed by qualified healthcare providers.
The findings of systematic reviews (SRs) on aromatherapy for cancer published in the last 10 years have been summarized below. The data presented within the illustrative tables in this section constitutes a concise summary of the information. A full description of the included SRs can be found in table 1.
Description of included studies
- Number of studies: total of 11 SRs (Liu 2024, Li 2022a, Shin 2016, Farahani 2019, Li 2022b, Liu 2022, Ahn 2024, Toniolo 2021, Ahn 2023, Cheng 2022, Corasaniti 2023).
Included RCTs across SRs: ranged from 8 to 31 RCTs per SR; participant numbers from 869 to 3239. - Participants: cancer patients with various cancers.
- Interventions: Aromatherapy by inhalation, massage, or both.
- Oils: Lavender (most frequent), chamomile, peppermint, ginger, rose, and mixtures.
- Comparators: Usual care, placebo, or no treatment.
- Outcomes: Anxiety and depression (6 SRs), chemotherapy-induced nausea and vomiting (5 SRs), pain (4 SRs), sleep (5 SRs) and fatigue (3 SRs), and quality of life (4 SRs).
Limitations of included studies
- Included SRs were all of low methodology.
- Methodological: Inconsistent reporting of intervention protocols and durations, High heterogeneity across included studies, small sample sizes in many RCTs.
- Data reporting: Some SRs excluded studies without complete data (Liu 2024), limited subgroup or sensitivity analysis to address heterogeneity.
- Effect size clinical relevance: Some significant findings had small effect sizes with limited clinical relevance.
Results for efficacy
- Mental health: moderate evidence of benefit for reducing anxiety while outcomes for depression were less consistent, with most reviews showing no or minimal effect. Based on 6 SRs.
- Chemotherapy-induced nausea and vomiting: Based on 5 SRs (see tables 1 and 3): results are not fully conclusive with some SRs showing benefits and others not.
- Sleep and fatigue; moderate evidence for improving sleep (5 SRs) but not fatigue (3 SRs) for which conflicting results are available.
- Pain: inconsistent results from 4 SRs with SR showing positive results while others either report non-significant results or only partial improvements in specific subgroups or delivery methods.
- Quality of life outcomes have contradictory evidence (3 SRs), as some SRs report benefits while others do not.
Mental health
Aromatherapy shows moderate evidence of benefit for reducing anxiety in cancer patients, while its effects on depression are less consistent.
Anxiety: Several systematic reviews (e.g., Liu 2024, Li 2022a/b, Liu 2022) reported statistically significant improvements in anxiety, with effect sizes ranging from small to moderate (SMDs between -0.43 and -0.70), though most had low quality and high or unclear risk of bias. One moderate-quality review (Li 2022b) also found a significant reduction in anxiety (SMD = -0.49).
Depression: Findings were weaker, while Liu 2024 and Liu 2022 showed small but significant improvements, other reviews (Li 2022a, Shin 2016, Li 2022b) found no significant effect or only partial benefits (e.g., with massage). Overall, aromatherapy appears more reliably effective for anxiety relief, especially through inhalation, while evidence for its impact on depression remains inconclusive.
Chemotherapy-induced nausea and vomiting
Across the studies reviewed, aromatherapy shows some potential benefit for managing chemotherapy-induced nausea and vomiting, though the strength of evidence varies. Results are not unanimous and had low or mixed quality, with methodological limitations and inconsistent risk of bias.
Sleep and fatigue
Evidence suggests that aromatherapy could improving sleep quality among cancer patients, while its impact on fatigue is modest and less consistent.
Sleep: Several low-quality systematic reviews (Ahn 2023, Cheng 2022, Liu 2024, Li 2022a) report significant improvements in sleep, with moderate to large effect sizes, particularly through inhalation and lavender oil massage.
Findings on fatigue are mixed: Liu 2024 and Farahani 2019 reported some benefit, while Ahn 2023 found no statistically significant effect.
Pain
Evidence for the use in pain management is mixed and inconclusive. The strongest support comes from Corasaniti 2023, a moderate-quality review that found a significant and large effect for essential oils in reducing pain. However, this review also included studies with some unclear risk of bias.
Other systematic reviews (Liu 2024, Li 2022a, Farahani 2019) with lower methodological quality reported little or no consistent benefit, with pooled results either non-significant or showing only partial improvements in specific subgroups or delivery methods (e.g., inhalation or gargle).
Please see table 1 for a full description of the included systematic reviews.
- The safety of aromatherapy depends on the respective essential oil used and their mode of administration.
- Topical use and inhalation of essential oils are generally considered safe when properly diluted and used appropriately.
- Oral ingestion of essential oils is not recommended due to risks of toxicity and adverse interactions.
- Please also refer to other CAM Cancer summaries on herbal products.
Adverse events
- Mild and transient side effects have been reported including headache and rash. (Cheng 2022, Toniolo 2021, Ahn 2024, Shin 2016)
- Serious adverse events are rare and mostly documented in case reports. (Posadzki 2012, NATMED 2025).
- Topical use risks include phototoxicity (e.g., bergamot), contact dermatitis, and rare endocrine effects (e.g., lavender, tea tree).
- Inhalation risks include rare cases of nasal irritation, eosinophilic pneumonia, and seizures linked to eucalyptus, camphor, rosemary. (Bahr 2019; Mathew 2020; Kodama 2022).
- (Accidental) oral use risks have been associated with seizures, hepatic failure, and other serious toxicities (Janes 2005; NatMed 2025)
Contraindications
- Allergy to specific oils or constituents.
- Pregnancy and lactation: Some oils (e.g., fennel, Thuja) show embryotoxic or teratogenic effects in preclinical studies. (Dosoky 2021, Shayan 2019, Dudipala 2021).
- Children: Increased risk of seizures and salicylate toxicity (especially with wintergreen). (Davis 2007, Sai 2021).
- Oestrogen-sensitive cancers: Lavender and tea tree oils linked to prepubertal gynecomastia (Henley 2007); caution advised
Interactions
- Interaction studies were performed in vitro and the actual clinical risks are unknown.
- Cytochrome P450 (CYP): Some oils (e.g., lavender, chamomile) may inhibit CYP enzymes, potentially affecting drug metabolism. (Mondal 2023, Ganzera 2006, Sheweita 2016).
- P-glycoprotein: Modulation by certain oils may alter drug transport. (Silva 2021)
- Chemotherapy: Orange oil may increase paclitaxel degradation in vitro. (Samide 2021)
- Immune checkpoint inhibitors: Immunostimulatory effects of some oils (e.g., eucalyptus, clove) are hypothesized but not confirmed. (Sandner 2020, Gostner 2014, Asif 2020)
- Hormonal therapies: Some oils (e.g., geranium, rose otto) may increase salivary oestrogen or show estrogenic activity in vitro. (Shinohara 2017).
Ahn JH, Kim M, Kim RW. Effects of aromatherapy on nausea and vomiting in patients with cancer: A systematic review and meta-analysis of randomized controlled trials. Complement Ther Clin Pract. 2024. doi: 10.1016/j.ctcp.2024.101838. (Ahn 2024)
Ahn JH, Kim M. Effects of Aromatherapy on Cancer Patients' Sleep and Fatigue: A Systematic Review and Meta-Analysis. J Integr Complement Med. 2023. doi: 10.1089/jicm.2022.0601. (Ahn 2023)
Cheng H, Lin L, Wang S, et al. Aromatherapy with single essential oils can significantly improve the sleep quality of cancer patients: a meta-analysis. BMC Complement Med Ther. 2022 doi: 10.1186/s12906-022-03668-0. (Cheng 2022)
Corasaniti MT, Bagetta G, Morrone LA, et al. Efficacy of Essential Oils in Relieving Cancer Pain: A Systematic Review and Meta-Analysis. Int J Mol Sci. 2023 doi: 10.3390/ijms24087085. (Corasaniti 2023)
Davis JE. Are one or two dangerous? Methyl salicylate exposure in toddlers. J Emerg Med. 2007 Jan;32(1):63-9. doi: 10.1016/j.jemermed.2006.08.009. PMID: 17239735.
Mondal G, Dale OR, Wang YH, Khan SI, Khan IA, Yates CR. In Vitro Metabolism and CYP-Modulating Activity of Lavender Oil and Its Major Constituents. Molecules. 2023 Jan 12;28(2):755. doi: 10.3390/molecules28020755. PMID: 36677813; PMCID: PMC9862203.
Dosoky NS, Setzer WN. Maternal Reproductive Toxicity of Some Essential Oils and Their Constituents. Int J Mol Sci. 2021 Feb 27;22(5):2380. doi: 10.3390/ijms22052380. PMID: 33673548; PMCID: PMC7956842.
Dudipala SC, Mandapuram P, Ch LK. Eucalyptus Oil-Induced Seizures in Children: Case Reports and Review of the Literature. J Neurosci Rural Pract. 2021 Jan;12(1):112-115. doi: 10.1055/s-0040-1721199.
Farahani MA, Afsargharehbagh R, Marandi F, et al. Effect of aromatherapy on cancer complications: A systematic review. Complement Ther Med. 2019 Dec doi: 10.1016/j.ctim.2019.08.003. (Farahani 2019)
Ganzera M, Schneider P, Stuppner H. Inhibitory effects of the essential oil of chamomile (Matricaria recutita L.) and its major constituents on human cytochrome P450 enzymes. Life Sci. 2006 Jan 18;78(8):856-61. doi: 10.1016/j.lfs.2005.05.095.
Gattefossé RM. Gattefossé's Aromatherapy. Edited by R Tisserand, Translated by L Davies. Saffron Waldon: The CW Daniel Company, 1993.
Groot de AC, Schmidt E. Essential Oils, Part IV: Contact Allergy. Dermatitis. 2016 Jul-Aug;27(4):170-5. doi: 10.1097/DER.0000000000000197. PMID: 27427818Henley DV, Lipson N, Korach KS, Bloch CA. Prepubertal gynecomastia linked to lavender and tea tree oils. N Engl J Med. 2007 Feb 1;356(5):479-85. doi: 10.1056/NEJMoa064725. PMID: 17267908.
Janes SE, Price CS, Thomas D. Essential oil poisoning: N-acetylcysteine for eugenol-induced hepatic failure and analysis of a national database. Eur J Pediatr. 2005 Aug;164(8):520-2. doi: 10.1007/s00431-005-1692-1. Epub 2005 May 14. PMID: 15895251.
Li D, Li Y, Bai X, et al. The Effects of Aromatherapy on Anxiety and Depression in People With Cancer: A Systematic Review and Meta-Analysis. Front Public Health. 2022;10:853056. doi: 10.3389/fpubh.2022.853056. (Li 2022b)
Li F, Jiang T, Shi T. Effect of inhalation aromatherapy on physical and psychological problems in cancer patients: Systematic review and Meta-analysis. J Psychosoc Oncol. 2022 doi: 10.1080/07347332.2021.2011529. (Li 2022a)
Liu T, Cheng H, Tian L, et al. Aromatherapy with inhalation can effectively improve the anxiety and depression of cancer patients: A meta-analysis. Gen Hosp Psychiatry. 2022. doi: 10.1016/j.genhosppsych.2022.05.004. (Liu 2022)
Liu Y, Xu M, Tian Q, et al. Effects of Aromatherapy on Physical and Psychological Symptoms in Cancer Patients: A Systematic Review and Meta-analysis. Cancer Nurs. 2024 doi: 10.1097/NCC.0000000000001384 (Liu 2024)
NMD, Natural Medicines Database. Aromatherapy [web resource, requires subscription], accessed 15th June 2025.
Perry N, Perry E. Aromatherapy in the management of psychiatric disorders: clinical and neuropharmacological perspectives. CNS Drugs 2006;20: 257-80.
Poma P, Labbozzetta M, Ramarosandratana AV, Rosselli S, Tutone M, Sajeva M, Notarbartolo M. In Vitro Modulation of P-Glycoprotein Activity by Euphorbia intisy Essential Oil on Acute Myeloid Leukemia Cell Line HL-60R. Pharmaceuticals (Basel). 2021 Jan 31;14(2):111. doi: 10.3390/ph14020111.
Posadzki P, Alotaibi A, Ernst E. Adverse effects of aromatherapy: a systematic review of case reports and case series. Int J Risk Saf Med. 2012 Jan 1;24(3):147-61. doi: 10.3233/JRS-2012-0568. PMID: 22936057.
Samide A, Tutunaru B, Varut RM, Oprea B, Iordache S. Interactions of Some Chemotherapeutic Agents as Epirubicin, Gemcitabine and Paclitaxel in Multicomponent Systems Based on Orange Essential Oil. Pharmaceuticals (Basel). 2021 Jun 27;14(7):619. doi: 10.3390/ph14070619.
Shayan, M., Mehrannia, K., Rastegar, T., Khanehzad, M., Ghantabpour, T., & Hassanzadeh, G. (2019). Teratogenic effect of the aqueous extract of the Foeniculum vulgare (fennel) on fetal development in mice. Journal of Contemporary Medical Sciences, 5(5), 258–263. https://doi.org/10.22317/jcms.v5i5.657
Sheweita SA, El-Hosseiny LS, Nashashibi MA. Protective Effects of Essential Oils as Natural Antioxidants against Hepatotoxicity Induced by Cyclophosphamide in Mice. PLoS One. 2016 Nov 1;11(11):e0165667. doi: 10.1371/journal.pone.0165667.
Shin ES, Seo KH, Lee SH, et al. Massage with or without aromatherapy for symptom relief in people with cancer. Cochrane Database Syst Rev. 2016 doi: 10.1002/14651858.CD009873.pub3 (Shin 2016)
Silva, N., Fortuna, A., Salgueiro, L., & Cavaleiro, C. (2021). The essential oil from the fruits of Peucedanum oreoselinum (L.) Moench (Apiaceae) as a natural source of P-glycoprotein inhibitors. Journal of Herbal Medicine, 29, 100482. 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.
Toniolo J, Delaide V, Beloni P. Effectiveness of Inhaled Aromatherapy on Chemotherapy-Induced Nausea and Vomiting: A Systematic Review. J Altern Complement Med. 2021. doi: 10.1089/acm.2021.0067 (Toniolo 2021)
Kim HJ, Hong JH. Multiplicative Effects of Essential Oils and Other Active Components on Skin Tissue and Skin Cancers. Int J Mol Sci. 2024 May 15;25(10):5397. doi: 10.3390/ijms25105397.
Li D, Li Y, Bai X, Wang M, Yan J, Cao Y. The Effects of Aromatherapy on Anxiety and Depression in People With Cancer: A Systematic Review and Meta-Analysis. Front Public Health. 2022 May 30;10:853056. doi: 10.3389/fpubh.2022.853056.
Liu T, Cheng H, Tian L, Zhang Y, Wang S, Lin L. Aromatherapy with inhalation can effectively improve the anxiety and depression of cancer patients: A meta-analysis. Gen Hosp Psychiatry. 2022 Jul-Aug;77:118-127. doi: 10.1016/j.genhosppsych.2022.05.004.
Lu X, Friedrich LJ, Efferth T. Natural products targeting tumour angiogenesis. Br J Pharmacol. 2025 May;182(10):2094-2136. doi: 10.1111/bph.16232.
Manjamalai A, Grace B. Chemotherapeutic effect of essential oil of Wedelia chinensis (Osbeck) on inducing apoptosis, suppressing angiogenesis and lung metastasis in C57BL/6 mice model, JCancer Sci. Ther., 5 (2013), pp. 271-281.
Sandner G, Heckmann M, Weghuber J. Immunomodulatory Activities of Selected Essential Oils. Biomolecules. 2020 Aug 3;10(8):1139. doi: 10.3390/biom10081139. PMID: 32756359
Citation
CAM Cancer Collaboration. Aromatherapy . July 2025
Document history
Summary fully updated in July 2025. “What is it” and “Does it work” sections updated by by Dana Mora and Barbara Wider, Update of “Mechanisms of action” and “Is it safe” sections by Lisa Dal Pozzo.
Summary updated in June 2020 by the CAM Cancer Collaboration, in May 2017 and December 2015 by Helen Seers; September 2013 and June 2012 by Katja Boehm.
Summary first published in March 2011, authored by Katja Boehm and Thomas Ostermann.
