In the framework of the design and development of TGR5 agonists, we reported that the introduction of a C(23)(S)-methyl group in the side chain of bile acids such as chenodeoxycholic acid (CDCA) and 6-ethylchenodeoxycholic acid (6-ECDCA, INT-747) affords selectivity for TGR5. Herein we report further lead optimization efforts that have led to the discovery of 6alpha-ethyl-23(S)-methylcholic acid (S-EMCA, INT-777) as a novel potent and selective TGR5 agonist with remarkable in vivo activity.