Patients between the ages of 15 and 80 years with clinical symptoms of acid regurgitation, heart burn, or feeling of acidity in the stomach, who have Los Angeles Grade A and B erosive esophagitis proven by endoscopy are recruited. Criteria for exclusions include (1) coexistence of peptic ulcer or gastrointestinal malignancies, (2) pregnancy, (3) coexistence of serious concomitant illness (for example, decompensated liver cirrhosis and uremia), (4) previous gastric surgery, (5) allergy to esomeprazole, (6) symptom score of a validated questionnaire (Chinese GERDQ) less than 12, and (7) equivocal endoscopic diagnosis of Los Angeles Grade A and B erosive esophagitis.