Aims To explore the differences between the probiotics adding and without on the gut microbiota, and to evaluate whether the probiotics can improve the gut microbiota or not.Methods We recruited 40 H.pylori infected patients with duodenal ulcer (DU) who were randomized into a triple-plus-probiotics (TP) group and a triple-only treatment (TT) group.Twenty cases of health people as health control (HC) group were also recruited.All the clinical symptoms and side effects during or after the treatment were observed and recorded.