The purpose of this study is to evaluate whether Rebamipide facilitate the healing of inflamed mucosa as an adjuvant regimen in erosive reflux esophagitis (ERE).

1. To evaluate whether Rebamipide facilitate the healing of inflamed mucosa as an adjuvant regimen in erosive reflux esophagitis patients
2. To evaluate the safety of rebamipide as an adjuvant regimen in erosive reflux esophagitis (ERE)

Inclusion Criteria:

1. Male/female patients aged 20 to 70 at the time of writing an informed consent.

2. Subjects who were diagnosed with Erosive Reflux Esophagitis (ERE) using Los Angeles (LA) classification grade A~D, confirmed by endoscopy.

3. The subjects regardless of presence of ERE symptom (i.e., symptomatic ERE or asymptomatic ERE).

   For symptomatic ERE, the subject must have one or more symptoms of the followings: acid regurgitation, heartburn, epigastric pain, cough, hoarseness, globus pharyngis, atypical chest pain.

4. Subjects who have consented to participate in this clinical study by signing an informed consent form.

Exclusion Criteria:

1. Patients with known hypersensitivity to any component of Lanston® and/or Mucosta® formulations.
2. Other concurrent organic upper gastroesophageal disease in endoscopy (i.e., drug-induced esophagitis, viral esophagitis, Mallory-Weiss syndrome, peptic ulcer disease, malignancies) and patients who was diagnosed with Barrett's esophagus.
3. History of abdominal surgery that can affect gastrointestinal motility (except appendectomy and hysterectomy).
4. History of upper gastrointestinal bleeding or obstruction.
5. Patients administrated with any drugs that can affect the efficacy of study regimen (proton pump inhibitors, revaprazan, prokinetics, H2-blockers, etc.) within 2 weeks (however, 4 weeks for PPIs) prior to enrollment and/or those who are required of NSAIDs, anti-coagulants, anti-cholinergics, prostaglandin E, corticosteroids, and anti-depressants treatment during the study period.
6. History of pancreatobiliary disease (except asymptomatic gallbladder stone), inflammatory bowel disease, cirrhotic liver disease, chronic kidney disease.
7. Pregnant, nursing, and childbearing potential women who is unwilling to effective contraception; for example, oral contraceptives, hormonal methods, placement of an intrauterine device (IUD) or intrauterine system (IUS), barrier methods (i.e., condom or occlusive cap with spermicidal foam/gel/film/cream/suppository), male sterilization, and true abstinence.
8. History of psychological disorder, alcoholics, and drug abuser.
9. Blood test results of hemoglobin (Hb) ≤ 10.0 g/dL, platelets ≤ 50,000 /µL, total WBCs ≤ 4,000/µL or ≥ 10,000/µL, and with serum test results showing the levels of AST, ALT, ALP, BUN, and creatinine exceeding twice the normal range of respective institution.
10. Patients who previously underwent another clinical survey within 4 weeks.
11. History of major medical disease that can affect general condition and other patients deemed not eligible for this study by investigators.