METHODS: CINAHL, PubMed, and EBSCO Host and Science Direct databases were searched for articles related to the use of EOs and/or aromatherapy for nausea and vomiting. Only articles using English as a language of publication were included. Eligible articles included all forms of evidence (nonexperimental, experimental, case report). Interventions were limited to the use of EOs by inhalation of their vapors to treat symptoms of nausea and vomiting in various conditions regardless of age group. Studies where the intervention did not utilize EOs or were concerned with only alcohol inhalation and trials that combined the use of aromatherapy with other treatments (massage, relaxations, or acupressure) were excluded.
RESULTS: Five (5) articles met the inclusion criteria encompassing trials with 328 respondents. Their results suggest that the inhaled vapor of peppermint or ginger essential oils not only reduced the incidence and severity of nausea and vomiting but also decreased antiemetic requirements and consequently improved patient satisfaction. However, a definitive conclusion could not be drawn due to methodological flaws in the existing research articles and an acute lack of additional research in this area.
CONCLUSIONS: The existing evidence is encouraging but yet not compelling. Hence, further well-designed large trials are needed before confirmation of EOs effectiveness in treating nausea and vomiting can be strongly substantiated.
DESIGN: Single-blind, controlled, randomized cross-over study. Patients received 5-day aromatherapy treatment using either ginger essential oil or fragrance-matched artificial placebo (ginger fragrance oil) which was instilled in a necklace in an order dictated by the treatment group sequence.
SETTING: Two oncology clinics in the East Coast of Peninsular Malaysia.
MAIN OUTCOME MEASURES: VAS nausea score, frequency of vomiting and HRQoL profile (EORTC QLQ-C30 scores).
RESULTS: Sixty female patients completed the study (age=47.3±9.26 years; Malay=98.3%; on highly emetogenic chemotherapy=86.7%). The VAS nausea score was significantly lower after ginger essential oil inhalation compared to placebo during acute phase (P=0.040) but not sustained for overall treatment effect (treatment effect: F=1.82, P=0.183; time effect: F=43.98, P<0.001; treatment×time effect: F=2.04; P=0.102). Similarly, there was no significant effect of aromatherapy on vomiting [F(1, 58)=0.29, P=0.594]. However, a statistically significant change from baseline for global health status (P<0.001) was detected after ginger essential oil inhalation. A clinically relevant 10 points improvement on role functioning (P=0.002) and appetite loss (P<0.001) were also documented while patients were on ginger essential oil.
CONCLUSION: At present time, the evidence derived from this study is not sufficiently convincing that inhaled ginger aromatherapy is an effective complementary therapy for CINV. The findings for HRQoL were however encouraging with significant improvement in several domains.