This Phase 4, multicenter, randomized, double-blind, active-controlled, non-inferiority study aims to evaluate the non-inferiority of Stoem Tab. compared to Stillen Tab. (Dong-A ST Co., Ltd.) in patients with acute or chronic gastritis. Participants will receive either Stoem Tab. or Stillen Tab. for 2 weeks. The primary outcome is the effective rate of gastric mucosal erosion at Week 2, assessed by upper gastrointestinal endoscopy and evaluated by an independent reviewer, defined as the proportion of participants achieving at least a 50% improvement in erosion score compared to baseline.

This Phase 4 clinical trial will assess the efficacy and safety of Stoem Tab. compared to Stillen Tab. in adults with acute or chronic gastritis. Participants will be randomized in a double-blind, parallel, active-controlled design to receive either Stoem Tab. or Stillen Tab. for 2 weeks. The primary endpoint is the effective rate of gastric mucosal erosion at Week 2, assessed by upper gastrointestinal endoscopy and evaluated by an independent reviewer. A responder is defined as a participant whose erosion score at Week 2 has improved by at least 50% compared to baseline (i.e., a decrease from grade 4 to grade 2 or 1, or from grade 3 or 2 to grade 1). The effective rate is calculated as the proportion of responders among the evaluable participants. Secondary endpoints include additional efficacy and safety evaluations. The study aims to demonstrate the non-inferiority of Stoem Tab. to Stillen Tab. All participants will be monitored for efficacy, safety, and medication compliance, and standard eligibility criteria will be applied.

Inclusion Criteria:

1. Male or female adults aged 19 to 75 years at the time of screening.
2. Participants diagnosed with acute or chronic gastritis by upper gastrointestinal endoscopy performed within 7 days prior to randomization (Visit 2), with at least one gastric erosion confirmed. Erosions of the esophagus and duodenum are excluded.
3. Female participants of childbearing potential or male participants who agree to maintain sexual abstinence or use appropriate contraceptive methods during the study period and for 2 weeks after the last administration of the investigational product. Periodic abstinence, such as calendar, ovulation, symptothermal, or post-ovulation methods, is not considered an acceptable contraceptive method.
4. Participants who voluntarily provide written informed consent to participate in this clinical trial.

Exclusion Criteria:

1. Participants with any of the following lesions confirmed or accompanied by upper gastrointestinal endoscopy at screening (Visit 1): active or healing peptic ulcer; reflux esophagitis; Barrett's esophagus greater than 3 cm; gastroesophageal varices; esophageal stricture; or other clinically relevant lesions. Participants with ulcer scars may be enrolled.
2. Participants who have a history of gastric acid secretion-inhibiting surgery or gastric or esophageal surgery at screening (Visit 1).
3. Participants who have been diagnosed with or have a history of Zollinger-Ellison syndrome at screening (Visit 1).
4. Participants with inflammatory bowel disease, such as Crohn's disease, ulcerative colitis, or intestinal Behcet's disease; primary esophageal motility disorder; or pancreatitis at screening (Visit 1).
5. Participants with a history of malignancy within 5 years prior to screening (Visit 1). However, participants who have been completely treated and have had no recurrence for at least 5 years may be enrolled at the investigator's discretion. Participants with gastrointestinal malignancy are excluded regardless of the time since diagnosis. Participants with basal cell carcinoma, squamous cell carcinoma of the skin, thyroid cancer, or carcinoma in situ of other sites may be enrolled at the investigator's discretion if they have been completely treated and have had no recurrence for at least 3 years.
6. Participants with current or prior thrombotic disease at screening (Visit 1), such as cerebral thrombosis, myocardial infarction, thrombophlebitis, or venous thrombosis.
7. Participants diagnosed with disseminated intravascular coagulation at screening (Visit 1).
8. Participants with concomitant hepatic, renal, cardiac, pulmonary, hematologic, or other diseases that, in the investigator's judgment, may affect the efficacy or safety evaluations.
9. Participants with current or prior lipid metabolism disorders at screening (Visit 1), such as hyperlipidemia or diabetic hyperlipidemia, or participants who require cautious administration of lipid nutritional products. However, participants whose condition is adequately controlled with medication may be enrolled at the investigator's discretion.
10. Participants with hereditary problems such as galactose intolerance, Lapp lactase deficiency, or glucose-galactose malabsorption.
11. Participants with a history of hypersensitivity to soybean, peanut, or soybean oil.
12. Participants with a history of hypersensitivity to any component of the investigational products, such as tartrazine.
13. Participants with clinically significant psychiatric disease at screening (Visit 1).
14. Participants who meet any other exclusion criteria related to prior or concomitant medications specified in the protocol.