Though primary and secondary duodenogastric reflux (DGR) have been accepted in the medical literature as separate clinical units, reliable and standardised methods of detection have not been known since long. Therefore, the role of DGR in the pathogenesis of upper GI tract diseases makes a problem. So far applied measurement techniques allow only indirect diagnosis of DGR, which is often unphysiological and not objective. These methods do not allow also quantitative evaluation. Unsatisfying results obtained with the use of these methods and further search for the effective system of 24-hour monitoring of bilirubin concentration, which is indirect marker of alkaline reflux Bilitec 2000 is the most physiologic technique of ambulatory recording of the retrograde duodenogastric reflux. It makes possible objective diagnosing of alkaline gastritis as a result of excessive exposure of gastric mucose to destructive effect of bile and pancreatic juice.