Highlights:
1. Intestinal flora enzymes metabolize small molecules of bile acid.
2. Multiple configurations of bile acids regulate Th17 and Treg cells and affect the intestinal immunity.
3. Bile acid molecules regulate the intestinal immune microenvironment by activating or inhibiting FXR and TGR5 in immune and intestinal epithelial cells.
4. Agonists and antagonists targeting FXR and TGR5 show great promise for alleviating intestinal inflammation and treating tumors.