Hospitals offer aromatherapy for nausea, and the best-supported sniff isn’t an oil

Key takeaways

• A 2018 Cochrane review of 16 studies found moderate-certainty evidence that sniffing isopropyl alcohol, the liquid in an alcohol prep pad, eased nausea after surgery sooner than standard anti-nausea drugs; peppermint oil did no better than a placebo¹.
• Nurses at 10 Allina Health hospitals in Minnesota and Wisconsin gave aromatherapy during 10,262 hospital stays, mostly lavender and ginger by inhalation, and patients’ symptom ratings dropped, though the study had no comparison group⁶.
• The famous story of René-Maurice Gattefossé plunging a burned hand into lavender oil is fiction, says Robert Tisserand, who edited the English edition of Gattefossé’s 1937 book; in the chemist’s own account, he rinsed the wounds with lavender essence after infection set in³⁴.
• No license is required to practice aromatherapy in the United States, and the two main U.S. training standards ask for anywhere from 50 to 400 hours, depending on the group and level²¹⁰¹¹.
• Before booking a session or buying oils, ask about training hours, the plant’s Latin name and screening for asthma, seizures and allergies⁸¹⁰¹¹.

In 2018, Cochrane reviewers pooled the research on aromatherapy for nausea after surgery. They found 16 studies with 1,036 patients¹.

The scent with the best support wasn’t peppermint, ginger or any other essential oil. It was isopropyl alcohol, the same liquid that soaks an alcohol prep pad¹.

In three small studies, patients who sniffed it got halfway relief from nausea faster than patients given standard anti-nausea drugs¹. That was one of the few findings the reviewers rated moderate certainty. Peppermint oil, tested in four small studies, did no better than a placebo five minutes after treatment¹.

That surprise says a lot about aromatherapy today. It isn’t one practice. It’s a French word coined in 1937, a nursing tool on hospital wards, an add-on at massage studios, and a diffuser on a kitchen counter².

This guide covers where aromatherapy came from, how each method works, what hospitals do with it, who’s trained to offer it, and what to ask before you pay. Our companion report card rates the evidence for 10 popular oils one by one.

A French chemist named it, and his burn story grew in the retelling

René-Maurice Gattefossé was a French chemist and perfumer. He coined the word “aromatherapy” and published a book by that name in Paris in 1937²³.

The book proposed using plant oils for diseases in nearly every organ system. The National Cancer Institute (NCI) notes that it rested mostly on anecdotes and individual cases².

The most famous case was his own. According to the description of the 1993 English edition, a laboratory explosion in 1910 left Gattefossé’s hands badly burned³.

The aromatherapy author Robert Tisserand has posted Gattefossé’s account from that edition on his blog. Gattefossé wrote that he smothered the flames by rolling on a lawn. Gas gangrene, a fast-spreading infection, then set in on both hands. A single wash with lavender essence halted it, he said, and the wounds began to heal a day later⁴.

Many retellings changed the story. In the popular version, he plunges his burned hand into the nearest vat of lavender oil on instinct. Tisserand, who edited the 1993 English translation, calls that detail fiction and reads the lavender rinse as a deliberate choice³⁴.

How much weight can the story bear? It’s a single case, reported by the man himself in a book published 27 years later³⁴. Tisserand adds that the 1910 date rests only on Gattefossé’s word, and that the lavender oil he favored had some of its natural compounds removed⁴. It’s a meaningful founding story, not a clinical test.

After a mid-century decline, a French physician, Jean Valnet, revived interest²⁹. During World War II, Valnet used essential oils on soldiers’ wounds, according to McGill University’s Office for Science and Society⁵. His book The Practice of Aromatherapy appeared in 1982².

From there, aromatherapy spread to Britain and the United States⁹. Through the 1990s, nurses ran most of the English-language research, and nurses became the main practitioners in both countries².

Smell takes a shortcut to the brain’s emotional centers

Most aromatherapy works through your nose. NCI explains the leading idea: scent molecules latch onto smell receptors in the olfactory bulb, the brain’s smell-processing hub, and the signal travels on to the limbic system, which handles emotion².

Richard Doty, director of the Smell and Taste Center at the University of Pennsylvania, has likened scent to music⁷. Through repeated pairing, he told Penn Medicine, a smell can come to trigger relaxation, much as a familiar song can soothe⁷.

There’s a second possible route. In a rat study, researchers found fragrance compounds in the blood after inhalation, which suggests they might act on the body like a drug².

Still, NCI cautions that the brain explanation is largely theoretical, because few in-depth nerve studies back it up². Expectation, attention and a calm ritual may do part of the work. That doesn’t make the comfort less real. It does make fair testing hard, because people can smell which treatment they got¹.

Touch may matter too. A 2000 review of six studies of aromatherapy with massage found a mild, short-lived drop in anxiety, but its authors judged the evidence too weak to prove a benefit².

Six ways oils are used, and what each one asks of you

Essential oils are pressed or steam-distilled from plants. NCI notes that oils pulled out with chemical solvents don’t count as true essential oils, and that an oil’s chemistry shifts as it ages². This is how the main methods compare.

Method	How it’s done	What research shows	Main caution
Room diffuser	Oil spreads through the air of a room, or drops go on a tissue2	Studies are mostly small, and many reports lack controls2	Everyone in the room breathes it; one hospital pilot excluded people with asthma or sensitive airways8
Personal inhaler	A few drops on a cotton ball sealed in a bag, sniffed as needed8	Common in hospital programs; mostly before-and-after ratings678	Keeps the scent to one person; still skip it with a known plant allergy8
Steam	Drops added to hot water and breathed in2	Little direct research2	Strong exposure close to the face; one case report links inhaled aromatherapy to a skin rash9
Massage	Oil diluted in a carrier oil and rubbed into skin2	Mild, short-lived calm in small studies2	Allergic skin reactions; citrus oils on skin before sun exposure can cause phototoxicity, a sun-triggered skin reaction9
Bath, lotion or compress	Oils added to bath salts, lotions or dressings2	Little direct research2	Same skin cautions as massage9
Swallowing	Drops or capsules by mouth9	Rare in U.S. and U.K. aromatherapy; more common in France and Germany9	Swallowed oils can poison15

If someone swallows an essential oil, call Poison Help at 1-800-222-1222¹⁵. Call 911 for a seizure, trouble breathing or collapse.

Inside hospital programs: nurses, inhalers and a screening list

The largest look at hospital aromatherapy comes from Allina Health, a hospital system in Minnesota and western Wisconsin. Researchers reviewed electronic records from 10 of its hospitals, covering 10,262 hospital stays in which nurses offered essential oils⁶.

Lavender made up about half of the sessions. Ginger came next at 21%, followed by sweet marjoram at 12% and mandarin at 9%⁶. More than three-quarters of the sessions were inhaled⁶.

Patients rated their symptoms from 0 to 10 before and after. Ginger cut nausea ratings by about 2 points, and lavender and sweet marjoram each cut anxiety by about 2.7 points⁶. The study, published in 2016 in Complementary Therapies in Medicine, had no comparison group, so it can’t separate the oil from the nurse’s attention or the passing of time⁶.

At the Hospital of the University of Pennsylvania, aromatherapy became a nurse-driven practice written into nursing policy, starting on cancer units⁷. Nurses there used lavender for anxiety, peppermint and ginger for nausea, lavender lotion for hand massage, and personal inhalers that patients could take home⁷. Patients rated their symptoms before and after each session⁷.

A 2019 pilot on a post-surgery unit at Oregon Health & Science University shows how simple and cheap it can be⁸. Nurses put three drops of oil on a cotton ball, sealed it in a plastic bag, and let patients open it and sniff as needed⁸. The team priced the oil at 6 to 9 cents per two-drop dose⁸.

The OHSU pilot also listed who should skip it. That included people with asthma or reactive airways, ragweed or daisy-family allergies, seizure disorders, or severe heart, lung or kidney disease⁸. That list is worth borrowing at home.

For nausea after surgery, aromatherapy is an extra, not a replacement

The Cochrane review is the best summary of how well this works. Its authors rated each finding by certainty, a measure of how much confidence the evidence deserves¹.

What was tested	What the studies found	Our rating
Sniffing isopropyl alcohol vs. standard anti-nausea drugs	Faster halfway relief and fewer rescue doses in 3 to 4 small studies, moderate certainty1	Promising but early
Sniffing isopropyl alcohol vs. a saline sniff	The summary reports fewer rescue doses, but the pooled estimate in 4 studies was statistically unclear, very low certainty1	Not enough evidence
Any aromatherapy vs. placebo, need for rescue drugs	Fewer rescue doses in 7 studies with 609 people, low certainty1	Promising but early
Ginger, alone or in a blend	A ginger-spearmint-peppermint-cardamom blend and ginger alone beat a saline sniff in a 301-person trial1	Promising but early
Peppermint oil vs. placebo	No difference at 5 minutes in 4 studies with 115 people1	Not enough evidence
Nurse-given oils for nausea, anxiety and pain in the hospital	Ratings improved, but no comparison group6	Not enough evidence
Scented oils for anxiety during radiation therapy	No benefit in a 313-person double-blind trial2	Evidence says no, or unsafe
Aromatherapy as a cancer treatment	No published studies, NCI says2	Not enough evidence

The reviewers concluded that aromatherapy may be a useful add-on, but nothing shows it can replace anti-nausea medicine¹. None of the studies they reviewed reported side effects¹.

The radiation trial had a twist. The group that got only the plain carrier oil, with no essential oil, had the biggest drop in anxiety². In that trial, the scent added nothing the plain oil didn’t.

Anyone can call themselves an aromatherapist

In the United States and the United Kingdom, nobody needs a license to practice aromatherapy, and the U.S. has no shared professional standard, NCI says². A nurse or massage therapist who uses oils holds a license for that profession, not for aromatherapy.

Two nonprofit membership groups set voluntary U.S. training standards²¹⁰¹¹. They’re professional bodies for the field, and the AIA also enrolls businesses as members. Neither is a regulator.

The National Association for Holistic Aromatherapy (NAHA) has three levels, last updated in 2017¹⁰. Its Level 1 certified aromatherapist needs at least 50 hours of training, 20 oil profiles and 5 case studies. Its clinical level needs 300 hours, 20 case studies and a year of clinical experience¹⁰. The schools themselves give the exams¹⁰.

The Alliance of International Aromatherapists (AIA), founded in 2006, sets its own minimums: 100 hours for its foundation level, 200 for professional and 400 for advanced practitioners¹¹. Finishing 200 hours qualifies a student to sit for the Aromatherapy Registration Council’s exam¹¹.

The AIA’s own disclaimer says it doesn’t independently audit a school’s curriculum between filings¹¹. Its practice standards ask aromatherapists to stay within their training and refer clients to qualified professionals when needed¹².

So “certified” usually means certified by a school or a private group. If massage is part of the session, NAHA points to state and national massage boards for that training¹⁰.

Market estimates differ by billions of dollars

Essential oils are big business, but nobody agrees how big. Two market research firms put the 2025 global market at very different figures.

IMARC Group estimated $14.3 billion, with North America holding about 22%¹³. Global Market Insights estimated $28.3 billion worldwide, with $5.5 billion in the United States alone¹⁴. Treat both as industry estimates, which may define the market differently.

IMARC puts “spa and relaxation” uses at about 47% of the market¹³. It also notes that doTERRA and Young Living, two well-known oil companies, are based in Utah¹³. Our article on wellness multilevel marketing covers how oils sold through friends and distributors work.

How the law treats an oil depends on what the seller claims. Our lavender sleep article explains when a scent becomes a drug in the FDA’s eyes.

Respect for the tradition means treating oils as strong substances

Aromatherapy’s founders weren’t casual about plants. Gattefossé was a chemist, Valnet was a physician, and nurses built much of the early research². Gattefossé even favored lavender oil with certain compounds removed, because he considered them irritating⁴.

That’s a tradition worth honoring. It treats a few drops as a potent chemical mix, chosen for a reason and used with care. It also leaves room for what research can’t easily measure: the comfort of a familiar scent and someone’s hand on yours.

Questions readers ask

The bottom line

Aromatherapy began with a chemist’s book and a dramatic, self-reported burn story. It now ranges from hospital inhalers to home diffusers. For nausea after surgery, the research supports it as a modest extra, and the best-supported sniff is plain isopropyl alcohol rather than an essential oil.

Hospital programs show how to use it well: offer it alongside medicine, screen for asthma, seizures and allergies, and let patients rate how they feel. Before you pay for a session or a bottle, ask about training, ingredients and safety. Use scents for comfort, and keep your clinician in the loop for anything more.

Related reading

• Lavender is the best-studied sleep scent, though its trials can’t hide the smell
• Ten popular essential oils graded, and none earned our top rating
• Wellness MLMs sell real products and a business few people profit from
• What the letters after a practitioner’s name mean
• How state licensing works, and what it doesn’t promise

Sources

1. Hines S, Steels E, Chang A, Gibbons K. “Aromatherapy for Treatment of Postoperative Nausea and Vomiting.” Cochrane Database of Systematic Reviews, 2018, Issue 3, CD007598.pub3. cochranelibrary.com
2. National Cancer Institute. “Aromatherapy With Essential Oils (PDQ)–Health Professional Version.” NCI, updated October 31, 2024. cancer.gov
3. Gattefossé RM; Tisserand R, ed.; Davies L, trans. Gattefossé’s Aromatherapy (English edition of Aromathérapie, Paris, 1937). C.W. Daniel, 1993. Internet Archive record. archive.org
4. Tisserand R. “Gattefossé’s Burn.” RobertTisserand.com, April 2011 per the page address (quotes Gattefossé’s 1937 account from the 1993 English edition, which Tisserand edited; a personal blog). roberttisserand.com
5. McGill University Office for Science and Society. “Did You Know? History: Aromatherapy.” May 31, 2017. mcgill.ca
6. Johnson JR, Rivard RL, Griffin KH, Kolste AK, Joswiak D, Kinney ME, Dusek JA. “The Effectiveness of Nurse-Delivered Aromatherapy in an Acute Care Setting.” Complementary Therapies in Medicine, 2016 (eScholarship record). pubmed.ncbi.nlm.nih.gov
7. Penn Medicine News. “Aromatherapy: How Essential Are Essential Oils?” Penn Medicine, July 2016.
8. Hyde K, Kniest M. “Aromatherapy Pilot Project.” Evidence-Based Practice Fellowship presentation, Oregon Health & Science University, June 11, 2019. digitalcollections.ohsu.edu
9. National Cancer Institute. “Aromatherapy and Essential Oils (PDQ)–Health Professional Version.” Version published online April 21, 2016, NCBI Bookshelf.
10. National Association for Holistic Aromatherapy. “Educational Standards.” NAHA, standards updated April 2017; accessed October 2026. naha.org
11. Alliance of International Aromatherapists. “Recognized Schools” (educational standards). AIA, accessed October 2026. alliance-aromatherapists.org
12. Alliance of International Aromatherapists. “Standards of Practice.” AIA, accessed October 2026. alliance-aromatherapists.org
13. IMARC Group. “Essential Oils Market Size, Share, Trends and Forecast, 2026-2034.” Last updated October 5, 2026. imarcgroup.com
14. Global Market Insights. “Essential Oil Market.” Accessed October 2026.
15. Loden J. “What Are the Commonly Used but Potentially Toxic Essential Oils?” Tennessee Poison Center, Vanderbilt University Medical Center, May 3, 2016. vumc.org