Many individuals in the Western world are troubled by heartburn, acid regurgitation, abdominal pain (dyspepsia), or bowel habit disturbances; up to one in two subjects in cross sectional population based studies report such symptoms. Gastro-esophageal reflux (GERD) is probably the commonest chronic disease of the population of the Western world. The reported prevalence of symptomatic GERD has ranged, on average, from 15% to 25%. Similarly, dyspepsia is a common condition in the general population; the reported prevalence range in populations is 15-40%. The majority of patients have functional (or non-ulcer) dyspepsia in that they do not have any underlying structural explanation for their symptoms, such as peptic ulcer disease or reflux esophagitis. However, given the significant morbidity and absence from work associated with the condition, the pathogenesis and treatment of patients with dyspepsia still requires further research. Studies are thus needed to determine the long term effects of these symptoms on healthcare costs but in the short run to determine the correlation of symptoms to acid levels and acid exposure.