The effect of a long-term treatment (one to two years) with cimetidine (1.6 g per day) and an antacid (Regla pH) was evaluated in nine patients with a Barrett's oesophagus. The results showed that such long-term treatment had a beneficial effect on the symptoms and endoscopic signs of oesophagitis and on the healing of a Barrett's ulcer, but did not result in a regression of the squamocolumnar junction back towards the cardia. No significant changes were observed in the histological epithelial types in the biopsies taken below the squamocolumnar junction. No clinical or biochemical side-effects or changes in biochemical parameters were noted during this study.