The purpose of this study is to determine the production of mucin in GERD/RE subjects before and after 8 weeks of treatment with rabeprazole.

Enrolled patients will undergo collection of salivary and esophageal secretions. Subsequently, all patients will receive rabeprazole (20mg QD) for 8 weeks and will be re-endoscoped to confirm complete healing of reflux esophagitis. In patients with completely healed reflux esophagitis the second collection of salivary and esophageal secretion will be implemented. In both secretions, adequately coded for the laboratory Research Fellow (blinded in terms of which sample is collected before and which after treatment with rabeprazole) the content of mucin will be measured using commercially available assay and its secretion expressed in units per minute of collection time.

Inclusion criteria: 24 patients with endoscopically confirmed reflux esophagitis (Grades A-D according to LA classification) in patients with chronic symptoms of GERD (heartburn with or without regurgitation) between the age of 19 and 79, 12M & 12F, will be included.

Exclusion criteria: History of GI surgery, primary esophageal motor disorders, any systemic disease, history of drug or alcohol abuse, pregnancy or nursing, allergy to the same drug class as rabeprazole, the need for any concurrent therapy that affects salivary secretion (causing so-called "dry mouth syndrome").