Both antacids and H2 receptor antagonists have a potential role in treating peptic oesophagitis associated with acid reflux. The aim of this study is to assess the efficacy and tolerability of famotidine and alginate-antacid in children with endoscopically documented peptic oesophagitis. We compared clinical, endoscopic and histological response to alginate-antacid (1 tablet to be chewed 30 min after each meal and at bed time) or famotidine (1 mg/kg before supper at 7 pm) in 49 children (mean age 9 years, 34 males). Twenty-four of them were randomly allocated to alginate-antacid treatment (group A), twenty-five to famotidine (group B). Both treatments were protracted for six months and endoscopy was then repeated. Symptoms disappeared in 43.4% and improved in 47.8% of children of group A and disappeared in 91.6% of those of group B (p less than .05). Mean time for symptom disappearance was 17 weeks for group A and 5 weeks for group B (p less than .01). After six months, at endoscopy oesophagitis was healed in 43.4% in group A and in 41.6% of group B, the difference between the two groups was not significant, however the improvement of endoscopic grades induced by famotidine was significantly better (p less than .05). Histology showed a healed peptic oesophagitis in 52.2% of the children in group A and in 70.8% of group B (p less than .001). No toxicity was observed with either treatment. We conclude that famotidine is superior to alginate-antacid in treating peptic oesophagitis associated with acid reflux, since it induces a better symptomatic response and a greater improvement of endoscopic lesions.