Published online Dec 21, 2021. doi: 10.3748/wjg.v27.i47.8040
Peer-review started: May 26, 2021
First decision: June 17, 2021
Revised: June 30, 2021
Accepted: December 7, 2021
Article in press: December 7, 2021
Published online: December 21, 2021
Core Tip: Helicobacter pylori (H. pylori) infection causes abnormalities in the intestinal flora and increases gastric acid secretion-stimulating gastrointestinal hormones. In addition, the cellular components of H. pylori travel through the intestinal tract, causing an effect of bacterial infection on the immune system. Meta-analyses reported that colorectal adenoma and cancer increase in H. pylori-infected individuals, and this bacterium has also been reported to be involved in several other diseases. On the other hand, H. pylori infection is considered to suppress inflammatory bowel disease. However, few studies have reported on these issues, and further elucidation is required.