Aromatherapy vs Oral Ondansetron for Antiemetic Therapy Among Adult Emergency Department Patients

Background Information:

Nausea and/or vomiting are chief complaints that account over 4 million emergency department (ED) visits each year.1 Multiple studies have shown aromatherapy in the form of isopropyl alcohol “prep” pads to be effective in postoperative nausea and vomiting.2,3 More specifically in the ED, a single randomized controlled trial showed nausea relief with inhaled isopropyl alcohol when compared to placebo.4 The authors of this study decided to take it one step further in this placebo-controlled randomized control trial by comparing aromatherapy to oral ondansetron in ED patients with nausea and vomiting

Paper: April MD, et al. Aromatherapy Versus Oral Ondansetron for Antiemetic Therapy Among Adult Emergency Department Patients: A Randomized Controlled Trial. Ann Emerg Med. 2018 PMID: 29463461

Clinical Question:

  • How does aromatherapy using isopropyl alcohol compare to oral ondansetron as an antiemetic therapy among adult emergency department patients not requiring immediate IV access?

What They Did:

  • Single center, placebo-controlled, blinded randomized control trial at a single urban tertiary care academic hospital
  • Nursing staff notified investigators when potential study subjects presented at triage with nausea or vomiting as their chief complaint
  • Subjects were randomized to one of the following three arms:
    • Group 1: Inhaled isopropyl alcohol and 4mg oral ondansetron
    • Group 2: Inhaled isopropyl alcohol and oral placebo
    • Group 3: Inhaled saline solution placebo and 4mg oral ondansetron
  • Patients were instructed to take deep nasal inhalations of the study medications as frequently as required to achieve nasal relief
  • Data was collected at 10, 20, 30 and 60 minutes after medication administration and then hourly until treating providers made a disposition decision
  • To ensure blinding, packaging of all the pads were obscured and the subjects opened their own study medications.
    • If unwilling or unable, study investigators opened the pad at arm’s length to avoid detecting the pad’s scent.
    • Investigators also instructed patients to avoid describing pad’s scent to them or subsequent providers during their ED visit
  • Study participation did not prevent subjects from receiving routine care and subjects could receive rescue antiemetic therapy at any time

Inclusion Criteria:

  • Adult patients ≥ 18 years of age
  • Chief complaint of nausea or vomiting
  • Self-reported nausea severity of 3 or greater on a verbal numeric response scale (0 to 10)

Exclusion Criteria:

  • Altered mental status that precludes signed informed consent
  • Inability to inhale through the nose (ie. Rhinitis)
  • Known history of QT-segment prolongation
  • Clinical suspicion for serotonin syndrome
  • Pregnant patients
  • Recent intake of medications contraindicating alcohol administration (ie. Disulfram, Cefoperazone, Metronidazole)
  • Known allergy to isopropyl alcohol or ondansetron
  • Treating provider discretion
  • Patients with IVs placed or who received antiemetic therapy in triage (including aromatherapy)



  • Change in nausea from baseline to 30 minutes post-intervention described via 0 to 100 mm Visual Analog Scale (VAS)


  • Change in pain VAS score from baseline to 30 minutes post-intervention
  • Vomiting during ED stay
  • Receipt of rescue antiemetic medications during ED stay
  • Admission to the hospital
  • ED length of stay


  • 208 patients were screened for study inclusion, 61 subjects did not meet all inclusion and exclusion criteria and 25 declined to participate
  • Of the remaining 122 patients, 2 enrolled subjects withdrew leaving the rest to be randomized as follows:
    • 40 in Group 1: Aromatherapy + Oral Ondansetron
    • 40 in Group 2: Aromatherapy + Oral Placebo
    • 40 in Group 3: Inhaled Placebo + Oral Ondansetron
  • Baseline characteristics were comparable across all three groups, however there were fewer woman in group 2

Critical Results:

  • Compared with the inhaled placebo, both groups of inhaled isopropyl alcohol experienced lower mean nausea VAS scores
  • The groups exposed to inhaled isopropyl alcohol had better satisfaction scores at time of disposition (the lower the number the more satisfaction)
  • Subjects who received inhaled isopropyl alcohol had greater pain reduction compared to the placebo
  • No subjects received rescue antiemetics before measure of the primary outcome


  • First study to compare inhaled aromatherapy using isopropyl alcohol to not only placebo but also ondansetron
  • Helps answer a clinically relevant question regarding antiemetic therapy options
  • Enlisted nurses at triage to get patients before they received IV access or any therapy
  • Implemented an intricate blinding strategy and measured the effectiveness of their blinding by querying subjects, providers and investigators whether the study medication the subject received was a treatment or placebo
  • Offered rescue antiemetic therapy to patients in all groups
  • Investigators queried subjects about their overall satisfaction to the treatment they received
  • Included other secondary outcomes of interest to emergency physicians such as ED length of stay, receipt of rescue antiemetic therapy and hospital admission


  • Small sample size
  • Healthier patient population that didn’t have IV access thus limiting generalizability to more severely nauseated patients
  • Enrollment was convenience sample thus potentially introducing selection bias
  • Performed at a single urban academic center thus limiting external validity at other institutions
  • Exclusion of pregnant patients is a missed opportunity on a large population with this frequent chief complaint
  • Aromatherapy was compared to only one oral antiemetic therapy
  • 30 minutes as primary outcome measurement may not have been enough time for ondansetron to take effect
  • VAS scores to measure nausea and pain reduction are subjective


  • This study is immensely valuable and practice changing because it utilizes a simple and inexpensive agent with a frequently encountered chief complaint. If implemented at triage, immediate intravenous access may not always be necessary
  • Furthermore, this has the potential to provide more immediate relief than oral medications and thus leading to greater patient satisfaction. Although anecdotal, I personally have utilized inhaled aromatherapy for quite some time and usually see relief within seconds to minutes in patients actively vomiting
  • Comparing aromatherapy to oral antiemetic agents and finding it resulted in greater nausea relief than antiemetics alone means it can be used as yet another tool in patients who are refractory to the commonly used standard therapy
  • It’s important to note that the authors compared inhaled isopropyl alcohol to only one other antiemetic therapy. Future studies should consider comparing these therapies to determine which combination is most efficacious
  • The authors recognize the use of VAS scores being subjective and important to patient centered outcomes. Unfortunately, when measuring vague variables such as nausea and pain this is the best we have. In addition to including the percent of patients who vomited during their ED stay, the authors, although difficult to do, should have recorded the actual number of times patients vomited
  • The results of this study add to previous literature showing improved nausea reduction with inhaled isopropyl alcohol vs placebo in emergency department patients4
  • The authors justified their use of the 30-minute time mark as the time many physicians would consider an alternative agent if the patient continued having symptoms
  • Patient’s remaining care is underappreciated in this study. Faster relief of nausea and vomiting could have occurred as a result of fluid administration and treating the original underlying cause (ie. Headache, UTI, electrolyte abnormalities)

Author’s Conclusions:

  • Among ED patients with acute nausea and not requiring immediate intravenous access, aromatherapy with or without ondansetron provides greater nausea relief than oral ondansetron alone

Our Conclusion:

  • Inhaled isopropyl alcohol is a simple, quick and inexpensive intervention that could be combined with oral agents and utilized as an antiemetic in adult emergency department patients. The immediate relief of nausea and vomiting may also improve patient satisfaction and prevent intravenous catheter placement. Additional studies are needed when applying the results of this study to pregnant patients, children, and those with severe nausea and vomiting

Clinical Bottom Line:

  • Inhaled isopropyl alcohol pads are a simple and inexpensive intervention that should be added as another tool, among other antiemetic therapies, when treating adult emergency department patients with nausea and vomiting


For More Thoughts on This Topic Checkout:


  1. April MD, et al. Aromatherapy Versus Oral Ondansetron for Antiemetic Therapy Among Adult Emergency Department Patients: A Randomized Controlled Trial. Ann Emerg Med. 2018 PMID: 29463461
  2. Hines S, et al. Aromatherapy for treatment of postoperative nausea and vomiting. Cochrane Database Syst Rev. 2012 Apr 18; PMID: 22513952
  3. Teran L, et al. The effectiveness of inhalation isopropyl alcohol vs. granisetron for the prevention of postoperative nausea and vomiting. AANA J. 2007 Dec; PMID: 18179001
  4. Beadle KL, et al. Isopropyl Alcohol Nasal Inhalation for Nausea in the Emergency Department: A Randomized Controlled Trial. Ann Emerg Med. 2016 Jul; PMID: 26679977

Post Peer Reviewed By: Salim R. Rezaie, MD (Twitter: @srreziae)

Cite this article as: Mark Ramzy, "Aromatherapy vs Oral Ondansetron for Antiemetic Therapy Among Adult Emergency Department Patients", REBEL EM blog, December 3, 2020. Available at:

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