Eosinophilic oesophagitis (EO) is a chronic immune/antigen-mediated oesophageal disease, with the immune reaction most likely directed to foods but on occasion also to aeroallergens. Clinically, it is characterised by symptoms of oesophageal dysfunction in subjects who typically have other indicators of an atopic tendency. Older children (and adults) frequently present with dysphagia and can have strictures (which may require dilatation). The diagnosis is dependent on an eosinophil-predominant oesophageal inflammation, with 15 or more eosinophils per high-powered field, now generally accepted as a necessary cut-off level of infiltration, which together with other clinical data (eg, oesophageal pH/impedance studies) can help discriminate EO from other potential causes of symptoms such as gastro-oesophageal reflux disease. Recommended therapies, which may need to be long term, are dietary antigen exclusion (with elemental feeds or an exclusion diet) and/or topical corticosteroids.