GPBAR1 and irritable bowel syndrome: The increased expression of bile acid in fecal, primary bile acid in liver and bile acid receptor Takeda G protein-coupled receptor 5 (TGR5) in colon in most patients with IBS-D is closely related to the severity of diarrhea symptoms (Walters, 2021; Wei et al., 2021), and the TGR5-ECS-5-HT signaling pathway may play an important role in the pathophysiology of IBS (Tao et al., 2022).