Although regularly prescribed in children with poorly controlled asthma with or without symptoms of gastroesophageal reflux (GER), the benefit of proton-pump inhibitors (PPIs) in improving asthma control remains uncertain. In this study, 306 children with poorly controlled asthma were randomised to receive either lansoprazole or placebo for 24 weeks in addition to their regular asthma treatment.2012 The primary outcome measure was the change in the Asthma Control Questionnaire (ACQ) score at 24 weeks. The groups were well matched at baseline in regard to ACQ scores, lung function and the presence of comorbid conditions including GER. Overall, there were no differences in the ACQ score nor for any of the secondary outcome measures between the groups irrespective of GER status. There were more adverse events in terms of upper respiratory tract infection (P = 0.02), sore throat (P = 0.02), bronchitis (P = 0.04) and activity-related bone fractures (P = 0.06) in the lansoprazole group compared with placebo. This study suggests lansoprazole is not effective and may potentially be harmful in children with poorly controlled asthma. Concerns has been raised about the exponential use of PPIs in children over the past decade and their potential to cause adverse effects, and this study provides further evidence that we should exercise caution before reaching for the prescription pad.