The goal of this clinical trial is to investigate the efficacy and safety of Weifuchun tablet in treating gastric intestinal metaplasia in Helicobacter pylori-negative adults. The main questions it aims to answer are: Does Weifuchun tablet promote the regression of gastric intestinal metaplasia in individuals without Helicobacter pylori infection? What medical problems do participants experience when taking Weifuchun tablet? Researchers will compare the effectiveness of Weifuchun tablet in treating gastric intestinal metaplasia with that of folic acid, as suggested by the Chinese consensus on management of gastric epithelial precancerous conditions and lesions (2020). Participants will: Take Weifuchun tablets or folic acid every day for 6 months. Visit the clinic once every 4 weeks for checkups and tests.