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Aromatherapy: Practices & What Research Shows

What aromatherapy is, how it is delivered, what systematic reviews and NIH summaries say about sleep, anxiety, nausea and pain, how it is regulated, and the main cautions.

Content last updated . This page has not been medically reviewed.

Safety first. Natural products can cause side effects and interact with medicines. Read essential oil safety before you use anything on this page.

Quick answer
Aromatherapy means using essential oils from plants as a complementary health approach. [1] Research on it is mixed. Many trials are small, short and hard to blind, and the better reviews call the evidence low in quality. This page is information only. It does not say any oil treats, cures or prevents a disease.

What aromatherapy is

NIH's National Center for Complementary and Integrative Health describes aromatherapy as the use of essential oils from plants (flowers, herbs or trees) as a complementary health approach. The oils are most often used by inhaling them or by applying a diluted form to the skin. [1] The National Cancer Institute adds that essential oils are used with other complementary treatments, such as massage or acupuncture, and alongside standard medical treatment. [2]

For what essential oils are and how they differ from fragrance oils, see What are essential oils?.

Traditional use and professional practice

Traditional use (not proof of effect). Poison Control notes that many essential oils have a long history of medicinal use based largely on traditional medicine practices and folklore, and that few uses have been studied in a scientific way. [3] The story of how modern aromatherapy developed is on the history page.

Professional practice. The NCI summary says aromatherapy is not regulated by state law and no licensing is required to practice it in the United States. Practitioners often combine aromatherapy training with another licensed field, such as massage therapy, nursing, acupuncture or naturopathy. [2] See aromatherapists' training and certification and, for the wider field of complementary care, Massage & Bodywork.

How aromatherapy is delivered

MethodWhat the sources describeRead more
Indirect inhalationThe patient breathes in an essential oil by using a room diffuser, or drops on a tissue or cotton nearby. [2]More about Indirect inhalation →
Direct inhalationThe patient breathes in an essential oil by using an individual inhaler. [2]More about Direct inhalation →
MassageOne or more essential oils is diluted into a carrier oil and massaged into the skin. [2]More about Massage →
Other skin productsEssential oils may also be mixed with bath salts and lotions or applied to bandages. [2]More about Other skin products →

No sources we read give one correct amount or dilution, and this site does not give a chart. The types of oils and the ways they are combined vary with the practitioner's experience and training. [2]

What research shows

Reviews of trials give a mixed picture. The table lists what the sources we read found. "Promising but limited" and "mixed" are our labels.
QuestionWhat the source foundEvidence labelPopulation and form studied
SleepNIH says little rigorous research has been done on aromatherapy for insomnia. [1] A 2025 meta-analysis of 27 publications found inhalation aromatherapy relieved symptoms of insomnia that came with other conditions, but the studies were heterogeneous and often not blinded. [4]Promising but limitedAdults with sleep problems alongside other conditions; inhaled
Anxiety and moodNIH says it is unclear whether lavender aromatherapy helps anxiety, stress or depression symptoms. [5] A 2022 meta-analysis in cancer patients found lower anxiety and depression scores, but study quality was low and placebo also appeared effective in some studies. [6]MixedMostly people with cancer; mostly compared with usual care
NauseaA 2024 review summarized by NIH found inhaled peppermint oil particularly successful at reducing nausea and vomiting in patients with cancer undergoing chemotherapy. [7] A 2024 review after surgery rated the certainty of evidence as low. [8]Promising but limitedPatients with cancer; patients after surgery; inhaled
PainA 2024 meta-analysis in people with cancer found no statistically significant effect of aromatherapy on pain. [9] A 2025 meta-analysis found less pain and anxiety during needle procedures. [10]MixedPeople with cancer; adults having needle procedures
Treating a diseaseThe NCI summary says no studies of aromatherapy used to treat cancer have been published in a peer-reviewed scientific journal. [2]Proper evidence not foundWe searched the NCI PDQ summary and PubMed reviews for this page

Details by use are on essential oils for sleep, anxiety, stress and mood and nausea.

Why the results are hard to read

  • Smell is hard to hide. A person usually knows whether a scent is present, so trials are hard to blind. One review of insomnia trials noted lack of blinding as a common problem. [4]
  • Outcomes are often self-reported. A cancer-care review found that placebo appeared effective in some studies, so a good score does not prove the oil did the work. [6]
  • Trials differ. A review of inhaled aromatherapy for chemotherapy nausea found small samples and a wide variety of oils, methods and numbers of drops, so results could not be generalized. [11]
  • Very low quality for massage. A Cochrane review of massage with or without aromatherapy in people with cancer judged the evidence very low quality. [12]

Related pages

Inhalation aromatherapy, aromatherapy massage, aromatherapy in hospitals and palliative care and essential oil research.

Frequently asked questions

Does aromatherapy work?

For most uses the answer is not settled. Some reviews report small benefits for anxiety, nausea or sleep, but they also describe low-quality studies, little blinding and placebo effects. [6] [4] NIH says little rigorous research has been done on aromatherapy for insomnia. [1]

Is aromatherapy the same as essential oils?

Aromatherapy is a way of using essential oils, mainly by inhaling them or applying them diluted to the skin. [1] The oils themselves are covered on What are essential oils?.

Can aromatherapy replace medical treatment?

We found no source saying it can. The NCI summary says no studies of aromatherapy used to treat cancer have been published in a peer-reviewed journal, and describes it as used alongside standard medical treatment. [2] Ask your clinician before changing any treatment.

Is aromatherapy FDA approved?

The FDA says products marketed with drug claims must meet drug requirements such as approval, while cosmetics do not need approval before sale. [13] The NCI summary says aromatherapy products do not need FDA approval. [2]

Is it safe to swallow essential oils?

No source on this site recommends it. Poison Control warns of serious poisoning from misuse, and gives 1-800-222-1222 as the US poison center number. [3]

More details: evidence, limits and cautions

The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.

How aromatherapy products are regulated in the US
The FDA says how a product is regulated depends mainly on how it is intended to be used, judged from claims in labeling, websites and advertising. A product intended only to cleanse or to make someone smell good is a cosmetic. Claims that a product will relieve colic, ease pain, relax muscles, treat depression or anxiety, or help you sleep are drug claims. [13] Air fresheners and scented candles can fall under the Consumer Product Safety Commission. [13] See also who regulates essential oils.
Safety
  • Skin. The NCI summary says allergic reactions and skin irritation may occur when oils stay in contact with skin for long periods, and sun sensitivity may occur with citrus or other oils applied before sun exposure. [2] See skin reactions.
  • Natural does not mean safe. The FDA notes that many plants contain materials that are toxic, irritating or likely to cause allergic reactions on skin. [13]
  • Swallowing. Poison Control says misuse of essential oils can cause serious poisoning. [3] If someone has swallowed an essential oil, call Poison Help at 1-800-222-1222 (US); call 911 for collapse, seizure or trouble breathing. Read what poison centers say.
  • Lavender. NIH says aromatherapy with lavender oil is considered possibly safe but may cause headache or coughing, and little is known about its safety in pregnancy or breastfeeding. [5]
  • Hormone questions. NIEHS says the clinical cases linking essential oils to breast tissue growth in boys described skin use, not aromatherapy, and that more studies are needed to know whether the same applies to aromatherapy. [14]
  • Infants. NIH says menthol in peppermint oil should not be inhaled by or applied to the face of an infant or small child. [7]
  • Medicines. Poison Control says essential oils may interact with medications. [3] Ask a pharmacist or clinician and read medication interactions.

For pets, diffusers and asthma, see essential oils and pets, diffusers and asthma and breathing problems.

References
  1. Aromatherapy, NCCIH (NIH), last updated January 2020. Read 2026-10-23.
  2. Aromatherapy With Essential Oils (PDQ), Patient Version, National Cancer Institute. Read 2026-10-23.
  3. Essential oils: Poisonous when misused, Poison Control. Read 2026-10-23.
  4. Inhalation aromatherapy for the treatment of comorbid insomnia: a systematic review and meta-analysis, Chen HB et al., Front Psychiatry 2025, PMID 40230824. Read 2026-10-23.
  5. Lavender: Usefulness and Safety, NCCIH (NIH). Read 2026-10-23.
  6. Aromatherapy with inhalation can effectively improve the anxiety and depression of cancer patients: A meta-analysis, Liu T et al., Gen Hosp Psychiatry 2022, PMID 35617792. Read 2026-10-23.
  7. Peppermint Oil: Usefulness and Safety, NCCIH (NIH). Read 2026-10-23.
  8. Aromatherapy for the prevention of postoperative nausea and vomiting: A systematic review and meta-analysis, Wang JY et al., Tzu Chi Med J 2024, PMID 38993833. Read 2026-10-23.
  9. Effects of Aromatherapy on Quality Of Life and Pain In Patients With Cancer: A Meta-Analysis, Kang H et al., J Pain Symptom Manage 2024, PMID 39053746. Read 2026-10-23.
  10. The Efficacy of Aromatherapy on Pain and Anxiety During Needle-Related Procedures in Adults: A Systematic Review and Meta-Analysis, Sun C et al., J Pain Res 2025, PMID 40827258. Read 2026-10-23.
  11. Effectiveness of Inhaled Aromatherapy on Chemotherapy-Induced Nausea and Vomiting: A Systematic Review, Toniolo J et al., J Altern Complement Med 2021, PMID 34283916. Read 2026-10-23.
  12. Massage with or without aromatherapy for symptom relief in people with cancer, Shin ES et al., Cochrane Database Syst Rev 2016, PMID 27258432. Read 2026-10-23.
  13. Aromatherapy, US Food and Drug Administration. Read 2026-10-23.
  14. Essential Oils, National Institute of Environmental Health Sciences (NIH), last reviewed March 19, 2026. Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.