It is possible for duodenal ulcers to cause atrophic gastritis. Duodenal ulcer is a localized mucosal destruction and inflammatory reaction due to stronger injury factors and weakened defenses. Common etiologic factors include increased secretion of gastric acid and pepsin, Helicobacter pylori infection, and long-term use of nonsteroidal anti-inflammatory drugs. The main clinical manifestation is hunger pain, and it also causes reflux of bile, pancreatic fluid. The main causes of atrophic gastritis are Helicobacter pylori infection, non-steroidal anti-inflammatory drugs, bile, pancreatic fluid and intestinal fluid reflux, etc., which overlap with the etiology and clinical manifestations of duodenal ulcers, so duodenal ulcers are very likely to complicate with atrophic gastritis if they are not treated in time, or if they are not treated properly.