Gastro-oesophageal reflux, GORD is a common condition. It predisposes to 8arreU's oesophagus, a premalignant condition leading to oesophageal adenocarcinoma. Oesophageal cancer is one of the faster rising cancers in the Western world. Proton pump inhibitors are the standard pharmacological treatment for symptoms of GORD. The impact of these drugs in the prevention of complications of GORD is however still unclear. Using the general practice research database (GPRD), we looked at temporal trends of GORD incidence and prevalence in the UK as well as its associated complications of BarreU's oesophagus and oesophageal cancer. Parallel trends in peptic ulcer disease are also investigated. The effect of proton pump inhibition in the development of oesophageal cancer in acid reflux is explored . We explored factors known to influence the intragastric acid levels and prevalence of GORD eg Helicobacter pylori prevalence and obesity. The prevalence of other gastro-intestinal conditions as well as GORD in candidates for bariatric surgery is also assessed. Optimising acid reflux control in Barrett's oesophagus by means of lifestyle adaptations in conjunction with use of proton pump inhibition is also investigated. Finally, aspects of the pathophysiology of eosinophilic oesophagitis, a newly recognised condition, and its relationship with GORD are also examined.