A large systematic review and meta-analysis of observational studies has attempted to clarify whether medicines that suppress gastric acid increase the risk of recurrence of Clostridium difficile infection (CDI).1 Gastric acid suppression has been linked to both primary and recurrent CDI, but studies examining the association have found conflicting results. The US Food and Drug Administration (FDA) has issued a warning that proton pump inhibitors (PPIs) may be associated with an increased risk of C. difficile-associated diarrhoea.2 In 2013, Public Health England concluded that there was increasing evidence that acid-suppressing medications, including PPIs, may be a …