Proton pump inhibitors (PPIs) are widely used in Denmark as a treatment for gastrooesophageal reflux disease (GERD) in infants under 12 months of age. In this review, we investigated the efficacy and safety of treatment with PPI against GERD in infants. We found that PPIs increased ventricular pH in infants but without a decline in symptoms of GERD compared with placebo. More frequent and serious adverse effects were observed after PPI treatment than after placebo. The available published evidence indicates that PPIs cannot be recommended as a treatment for GERD in infants.