Objectives: The object of this study was to observe the suppressive effects of Yijintang-gamibang (YJGMB), Yijintang being traditionally used in the Korean Medicine for treating various digestive diseases, on the rat reflux esophagitis (RE) as compared with omeprazole, a well-known proton pump inhibitor. Methods: Three different dosages of YJGMB, 50, 100 and 200 mg/kg, were orally pretreated once a day for 28 days before pylorus and forestomach ligation. Seven groups of 8 rats each were used in the study. Six hrs after pylorus and forestomach ligation, changes to the stomach and esophagus lesion areas, gastric volumes, acid and pepsin outputs, invasive lesion percentages, fundic mucosa, esophageal submucosa and total thicknesses were measured by histomorphometry. The results were compared with omeprazole 10 and 30 mg/kg treated groups in which the effects on RE were already confirmed. Results: As results of pylorus and forestomach ligation, marked increases of esophageal and gastric mucosa lesion areas, gastric volumes, acid outputs, pepsin outputs were observed with histopathological changes of RE, such as hemorrhages, ulcerative lesions and edematous changes on the esophageal and fundic mucosa. However, these pylorus and forestomach ligation induced RE were dose-dependently inhibited by treatment of 50, 100 and 200 mg/kg of YJGMB. YJGMB 50 mg/kg showed similar suppressive effects as 30 mg/kg of omeprazole, but more favorable effects were observed as compared with omeprazole 10 mg/kg. Conclusion: The results suggest that YJGMB showed favorable suppressive effects on the RE induced by pylorus and forestomach ligation. It is therefore expected that YJGMB will show favorable effects on RE as corresponds to the suggestion of traditional Korean medicine. However, more detailed mechanism studies should be conducted in future with the screening of the biological active chemical compounds in herbs.