Proton pump inhibitors are often used to treat disorders associated with gastric hypersecretion in children, despite the lack of pediatric formulations. They are highly effective in the treatment of ulcers, gastro-esophageal reflux disorders and hypersecretory diseases. They provide a high level of gastric acid inhibition with few adverse effects. The aim of this article is to review the available studies concerning the use of proton pump inhibitors in pediatric populations and to point out: indications for use in children, optimal dosage, risk of adverse effects and consequences of the mechanism of action, and drug interactions. We performed a Medline and Embase search of publications printed from January 1980 to December 2002 concerning the use of proton pump inhibitors in children. We consider the available randomised controlled trials and several other uncontrolled studies conducted in the pediatric population, including all available information concerning the pediatric use of proton pump inhibitors. In children as well as in adults, there are clinical conditions (i.e., severe esophagitis or eradication of Helicobacter pylori) in which proton pump inhibitors offer clear advantages over histamine-2 receptor antagonists. The relatively common use of acid inhibitors (proton pump inhibitors and histamine-2 receptor antagonists) in uncomplicated gastro-esophageal reflux disorders or in the prevention of non-steroidal anti-inflammatory drugs/steroid gastropathy is often unsubstantiated and should be limited to very specific situations. Multicentre randomised controlled studies are needed to better define the efficacy profile, the optimal dosage with respect to the different indications and the safety profile for chronic therapy of proton pump inhibitors in children.