In the dextran sulfate sodium (DSS)-induced colitis model, berberine exerts its therapeutic effects by activating the mTORC1 signaling pathway to enhance the number of Treg cells and regulate the levels of intestinal microbiota-associated tryptophan metabolites and the activation of the aryl hydrocarbon receptor (Li Q. et al., 2019; Jing et al., 2021). The gene discussed is AHR; the disease is colitis.