This is a multicenter, active-controlled, randomized, double-blinded, paralleled group clinical study to evaluate the efficacy of 4-week treatment with Stillen tab. in patients with acute or chronic gastritis. Subject will receive Stillen tab or Mucosta tab., three times a day for four weeks.

Inclusion Criteria:

• Age is over 20 years old, under 75 years old, men or women
• Patients diagnosed with acute or chronic gastritis by gastroscopy
• Patients with one or more erosions found by gastroscopy
• Signed the informed consent forms

Exclusion Criteria:

• Patients with peptic ulcer and gastroesophageal reflux disease
• Patients administered with prokinetics, H2 receptor antagonists, proton pump inhibitors, anticholinergic drugs or non-steroid anti-inflammatory drugs prior to study in 2 weeks
• Patients with surgery related to gastroesophageal
• Patients with Zollinger-Ellison syndrome
• Patients with any kind of malignant tumor
• Patients administered with anti-thrombotic drugs
• Patients with significant cardiovascular, pulmonary, heptic, renal, hemopoietic or endocrine system primary disease
• Women either pregnant or breast feeding