BACKGROUND: Recent advances in eosinophilic oesophagitis (EoE) have confirmed the existence of a new disease phenotype, proton pump inhibitor (PPI)-responsive oesophageal eosinophilia (PPI-REE). AIM: To summarise evidence supporting the use of PPI therapy in patients with suspected EoE (oesophageal dysfunction plus >15 eos/HPF in oesophageal biopsies). METHODS: A literature search was conducted through MEDLINE, using the MeSH search terms 'eosinophilic oesophagitis', 'proton pump inhibitors' and 'oesophageal eosinophilia'. Relevant articles and their reference lists were identified through manual review. RESULTS: Ten articles, including 258 patients with suspected EoE (152 children, 106 adults) undergoing clinico-histological re-evaluation after PPI therapy, were identified. In children, clinical response ranged from 78% to 86% and histological remission from 23% to 40%. In adults, symptom response ranged from 25% to 80% and histological remission from 33% to 61%. Among PPI-REE patients with oesophageal pH-monitoring, 35 showed pathological and 10 normal studies. PPI-REE was significantly commoner with documented gastro-oesophageal reflux disease (GERD) when compared to patients with negative pH monitoring (70% vs. 29%, P < 0.001). Symptom improvement/resolution occurred in 50-85% of patients without histological remission on PPI therapy. Six PPI-REE patients demonstrated clinico-histological relapse on PPI therapy. CONCLUSIONS: At least one third of patients with suspected EoE achieve clinico-histological remission on PPI therapy. Response is more limited in children compared with that in adults. pH monitoring does not accurately predict response to PPI therapy, albeit histological remission is significantly higher, up to 70%, upon documented GERD. Symptom improvement is common with PPI therapy despite persistent eosinophilic infiltration.