Eosinophilic oesophagitis (EE) is a clinico-pathological entity recognized with increased frequency in children and adults. It is an atopic disease involving ingested and inhaled allergens. A pathological eosinophilic infiltrate is diagnosed by finding ≥ 15 eosinophils per high-powered field on oesophageal mucosal biopsies. This infiltrate may result in a narrowed oesophageal lumen. It does not involve the stomach or duodenum. Children commonly present with abdominal pain, vomiting and dysphagia. Presentation in adults is with dysphagia, heartburn, chest pain or impaction of a food bolus in the oesophagus. There is often a history of allergy (asthma, hay fever, eczema). A male predominance (70% in adults) is unexplained. Distinctive endoscopic features are linear furrows, mucosal rings and white papules, and the narrowed lumen may be appreciated. Although EE and gastro-oesophageal reflux disease are separate entities, there is a significant overlap of the conditions. Treatment options include nonpharmacological approaches including an elimination or elemental diet, and/ or medications, chiefly with corticosteroids. The topical administration of fluticasone propionate has been demonstrated to improve symptoms and mobilize the pathological infiltrate of eosinophils. There has been a variable effect with the leukotriene receptor antagonist montelukast and promising early results with mepolizumab, a monoclonal antibody against interleukin-5. The long-term efficacy of topical corticosteroids has not been well studied and most patients experience recurrent symptoms when treatment is completed. Currently, repeated short courses of topical corticosteroids are utilized. Acid suppression by a proton pump inhibitor may be considered in view of the overlap between EE and gastro-oesophageal reflux disease.