As one of the most widely consumed beverages globally, coffee's relationship with digestive health has drawn significant attention. Recent studies indicate that coffee exerts bidirectional regulatory effects on the occurrence and progression of gastric ulcers. On one hand, polyphenolic compounds such as chlorogenic acid in coffee exert protective effects on the gastric mucosa by inhibiting inflammatory responses and promoting the growth of beneficial gastrointestinal bacteria. On the other hand, caffeine stimulates gastric acid secretion through multiple signaling pathways, potentially increasing the risk of ulcer development. This article systematically elucidates the regulatory mechanisms of coffee's bioactive constituents in the pathological progression of gastric ulcers, based on evidence from in vivo, in vitro, and clinical studies. It further analyzes the association between coffee consumption and gastric ulcer risk across different populations. The aim is to provide scientific recommendations for coffee consumption to the public and to offer a theoretical basis for further research and applications of coffee in digestive health.