Written by Jessica Patella, ND. Aromatherapy with bitter orange (C. aurantium) significantly reduced the average severity of nausea, vomiting and retching within 5-days of chemotherapy treatment compared to the control group.  

Breast cancer is the most common cancer in women and the second most common cancer worldwide^1,2.  Common treatments for breast cancer include surgery, radiation and chemotherapy^1,3, yet chemotherapy is associated with numerous side effects, including nausea and vomiting^1,4.  Recent research has found aromatherapy of Citrus aurantium alleviated chemotherapy-induced nausea and vomiting¹.

An estimated 60% of patients experience nausea and 30% suffer from vomiting from chemotherapy, even with antiemetic drugs^1,5.  Bitter orange (Citrus aurantium) contains limonene that has been shown to affect serotonin and dopamine pathways, which are central to nausea and vomiting^1,6.

The recent research included a total of 92 breast cancer patients (stage 2 or 3) that were randomly assigned to a control group (n=46) or the aromatherapy group (n=46).  The participants in the aromatherapy group received bitter orange oil, where as those in the control group received sunflower oil (an odorless oil).  Intervention was conducted in the home of the participant.  The participants applied 2-drops of oil on the area between the upper lip and nose and were asked to breathe normally for 20-minutes, 3-times daily (9:00, 15:00, 21:00).  They were to apply the oil for 5-days post-chemotherapy and complete a Rhodes Index daily.  The Rhodes Index is used to assess nausea, vomiting and retching, with a higher number indicating greater severity⁷.  A range of 5-days was chosen because chemotherapy induced nausea and vomiting typically occurs between 24-hours to 5-days post-chemotherapy^1,7.

The results were as follows:

• Significant reductions in vomiting scores were observed in the aromatherapy group on day 3 (p=0.05), day 4 (p=0.04) and day 5 (p=0.01) compared to the control.
• Significant reductions in nausea scores were observed in the aromatherapy group on day 3 (p=0.01) and day 5 (p=0.004) and near significance on day 4 (p=0.06) compared to the control group.
• Significant reductions in retching scores were observed in the aromatherapy group on day 3 (p=0.02) and day 5 (p=0.020) and near significance on day 4 (p=0.06) compared to the control group.
• The overall symptom scores decreased in the aromatherapy group over the five days (6.29 +/- 5.80 vs 3.55 +/- 4.56). Significant reductions in overall symptom scores were observed in the aromatherapy group on day 3 (p=0.005), day 4 (p=0.02) and day 5 (p=0.002) compared to the control.

In conclusion, aromatherapy with bitter orange (C. aurantium) significantly reduced the average severity of nausea, vomiting and retching within 5-days of chemotherapy treatment compared to the control group.  Future research should consider a larger sample size and long-term efficacy of this simple intervention¹.

Source: Tabei, Parsa, Zahra Molazem, Mozhgan Rivaz, Parvin Ghaem Maghami, and Niloofar Ahmadloo. “The effect of Citrus aurantium inhalation aromatherapy on chemotherapy-induced nausea and vomiting in breast cancer patients: a randomized controlled trial.” BMC Complementary Medicine and Therapies 25, no. 1 (2025): 1-11.

© The Author(s) 2025. Open Access

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Posted December 9, 2025.

Jessica Patella, ND, is a naturopathic physician specializing in nutrition and homeopathic medicine and offers a holistic approach to health.  She earned her ND from Sonoran University (formerly Southwest College of Naturopathic Medicine in Tempe, AZ).  Dr. Patella has been involved in research since high school, when she presented her research at University of Florida on Group B Strep in pregnant women. While earning a bachelors in exercise physiology at Florida State University, her honors research was examining lifestyle effects on glucose levels in women. Dr. Patella was also a research assistant while in naturopathic medical school and has been writing for the Natural Health Research Institute since she graduated from Sonoran University in 2009. Dr. Patella currently teaches a variety of classes all related to human health.

References:

1. Tabei P, Molazem Z, Rivaz M, Maghami PG, Ahmadloo N. The effect of Citrus aurantium inhalation aromatherapy on chemotherapy-induced nausea and vomiting in breast cancer patients: a randomized controlled trial. BMC complementary medicine and therapies. Oct 7 2025;25(1):359. doi:10.1186/s12906-025-05052-0
2. Nardin S, Mora E, Varughese FM, et al. Breast Cancer Survivorship, Quality of Life, and Late Toxicities. Front Oncol. 2020;10:864. doi:10.3389/fonc.2020.00864
3. Madaminov M, Shernazarov F. Breast cancer detection methods, symptoms, causes, treatment. Science and innovation. 2022;1(D8):530–535.
4. Tang H, Zhang W, Shen H, et al. A protocol for a multidisciplinary early intervention during chemotherapy to improve dietary management behavior in breast cancer patients: a two-arm, single-center randomized controlled trial. BMC Cancer. Jul 18 2024;24(1):859. doi:10.1186/s12885-024-12623-w
5. Marx W, Kiss N, McCarthy AL, McKavanagh D, Isenring L. Chemotherapy-Induced Nausea and Vomiting: A Narrative Review to Inform Dietetics Practice. J Acad Nutr Diet. May 2016;116(5):819–27. doi:10.1016/j.jand.2015.10.020
6. Vieira AJ, Beserra FP, Souza MC, Totti BM, Rozza AL. Limonene: Aroma of innovation in health and disease. Chem Biol Interact. Mar 1 2018;283:97–106. doi:10.1016/j.cbi.2018.02.007
7. Rhodes VA, McDaniel RW. The Index of Nausea, Vomiting, and Retching: a new format of the lndex of Nausea and Vomiting. Oncol Nurs Forum. Jun 1999;26(5):889–94.