When evidence emerges that a readily available and safe drug can effectively treat a very common childhood illness, and hence prevent many hospital admissions, there is an understandable tendency for clinicians to jump on the bandwagon and use it extensively. This is what happened with Ondansetron, an anti-emetic originally intended for use in the severe nausea and vomiting seen with cancer chemotherapy, but which proved in some randomised controlled trials (RCTs) to be effective in ordinary childhood gastroenteritis (GE). Researchers from the US set out to look at changes in usage and apparent effectiveness of oral Ondansetron given to children under 18 with GE in emergency departments (EDs) (Freedman S et …