Chewy Trial

Project Details

A multi-centre randomized non-inferiority trial of chewing gum versus ondansetron to treat postoperative nausea and vomiting in female patients after breast or laparoscopic surgery (The Chewy Trial)

Nausea and vomiting are common and distressing side effects of anaesthesia. Chewing gum is a novel drug-free treatment that may be effective. The Chewy Trial is a large study in female surgical patients aged 12 years and over. Our aim is to determine if chewing gum is as good as standard treatment with intravenous ondansetron in achieving full resolution of nausea and vomiting after anaesthesia. This study has the potential to improve clinical and financial outcomes for millions of patients worldwide.

Primary hypothesis: Chewing gum is non-inferior to ondansetron in achieving full resolution of PONV for 2 hours after administration to female patients aged ≥12 years with PONV in the PACU after volatile anaesthetic-based general anaesthesia for breast or laparoscopic surgery.

Secondary hypotheses: Chewing gum is superior to ondansetron with respect to full resolution of PONV, acceptability of randomized treatment to patients and PACU nurses, time to full resolution of PONV, numbers of episodes of PONV after randomized treatment, numbers of rescue treatments after randomized treatment, duration of PACU stay, quality of recovery, functional health and well-being, duration of hospital stay, unplanned overnight admission in planned day cases, cost of randomized and rescue drugs, and hospital stay.

Safety hypotheses: Inhalation or swallowing of gum, unplanned admission of scheduled day cases, unplanned intensive care unit admission, cardiovascular, pulmonary and wound events, and death.

Follow Chewy on Twitter @ChewyTrial


Dr Jai Darvall
Prof Kate Leslie
Prof David Story
Prof Andrew Davidson
Ms Sabine Braat
Dr An Tran-Duy
Ms Cindy Schultz-Ferguson
Prof Julie Simpson
Dr Megan Allen
Prof Philip Clarke

Research Publications

Darvall JN, Handscombe M, Leslie K. Chewing gum for the treatment of postoperative nausea and vomiting: a pilot randomized controlled trial. Br J Anaesth. 2017 Jan;118(1):83-89. doi: 10.1093/bja/aew375.

Media Mentions

Gum rolled out in hospitals as latest treatment to help patients recover from surgery, Herald Sun, 10th July 2018.

Research Group

Anaesthesia, Perioperative and Pain Medicine

School Research Themes

Critical Care

Key Contact

For further information about this research, please contact the research group leader.

Department / Centre

Critical Care

MDHS Research library
Explore by researcher, school, project or topic.