Indole-3-acetic acid (IAA), as a tryptophan catabolite and a microbiota-derived ligand of the aryl hydrocarbon receptor (AHR) which regulates AhR-dependent IL22 and Reg3g expression, strengthened the integrity of intestinal mucosa and reduced alcoholic-related liver inflammation (Roager and Licht, 2018). This evidence concerns the gene AHR and Hepatitis.