The goal of this clinical trial is to investigate the efficacy of ursodeoxycholic acid in treating gastric intestinal metaplasia in Helicobacter pylori-negative adults. It will also learn about the safety of ursodeoxycholic acid. The main questions it aims to answer are:

Does ursodeoxycholic acid promote the regression of IM in individuals without Helicobacter pylori infection? What medical problems do participants experience when taking ursodeoxycholic acid? Researchers will compare ursodeoxycholic acid to a placebo (a look-alike substance that contains no drug) to see if ursodeoxycholic acid is effective in treating gastric intestinal metaplasia.

Participants will:

Take ursodeoxycholic acid or a placebo every day for 6 months. Visit the clinic once every 4 weeks for checkups and tests.

Inclusion Criteria:

• patients aged from 18 to 75 years old.
• patients with OLGIM stage Ⅱ-Ⅳ diagnosed by upper gastrointestinal endoscopy and histopathological examination within the last 3 months.
• patients without Helicobacter pylori infection, including patients who had successful Helicobacter pylori eradication before enrollment.

Exclusion Criteria:

• a history of regular use (defined as at least once per week) of non-steroidal anti-inflammatory drugs (NSAIDs) and/or statins.
• a history of stomach surgery (including endoscopic submucosal dissection and endoscopic mucosal resection) or previously diagnosed malignant tumor.
• a history of heart failure, renal failure, liver cirrhosis or chronic hepatic failure; patients with contraindications or allergies to the drugs in this study.
• breastfeeding or pregnancy.
• a history of substance abuse or alcohol abuse within the past one year.
• patients with severe mental illness.
• refusal to undergo drug treatment.
• refusal to sign informed consent.