Clinical trial: oral ondansetron for reducing vomiting secondary to acute gastroenteritis in children – a double-blind randomized study H. L. YILMAZ*, R. D. YILDIZDAS  & Y. SERTDEMIR à *Department of Pediatric Emergency Medicine, Medical School of Cukurova University, Adana, Turkey;  Department of Pediatric Intensive Care Medicine, Medical School of Cukurova University, Adana, Turkey; àDepartment of Biostatistics, Medical School of Cukurova University, Adana, Turkey Correspondence to: Dr H. Levent Yilmaz, Yenibaraj M. 68001 S. Gulek Plaza A Blok 6 / 9 01150 Seyhan, Adana, Turkey. E-mail: hyilmaz@cu.edu.tr Publication data Submitted 17 July 2009 First decision 31 July 2009 Resubmitted 12 September 2009 Accepted 13 September 2009 Epub Accepted Article 16 September 2009 SUMMARY Background Vomiting as a consequence of gastroenteritis frequently occurs in chil- dren. It is still debatable whether vomiting should be treated with antie- metic drugs. Aim To investigate potential beneficial effects of ondansetron in treating vomiting during acute gastroenteritis. Methods A randomized, double blind, placebo-controlled trial was performed in our emergency departments. Children, aged 5 months to 8 years, were randomized to receive either ondansetron 0.2 mg / kg or placebo at 8h intervals. The primary outcome measure was the frequency of emesis during an 8-h-period after enrolment. Results A hundred and nine patients were enrolled; 54 received placebo and 55 received ondansetron. As compared with the children who received pla- cebo, children who received ondansetron were less likely to vomit both during the first 8-h follow-up in the emergency department [relative risk (RR): 0.33, 95% CI: 0.19–0.56, NNT: 2, 95% CI: 1.6–3.5], and during the next 24-h follow-up (RR: 0.15, 95% CI: 0.07–0.33, NNT: 2, 95% CI: 1.3–2.1). Conclusion Ondansetron may be an effective and efficient treatment that reduces the incidence of vomiting from gastroenteritis during both the first 8 h and the next 24 h, and is probably a useful adjunct to oral rehydration. Aliment Pharmacol Ther 31, 82–91 Alimentary Pharmacology & Therapeutics 82 ª 2010 Blackwell Publishing Ltd doi:10.1111/j.1365-2036.2009.04145.x