Due to their essential role in the gut-liver-brain axis and their physiological and pathological implications in both normal brain function and a number of neurological illnesses, bile acids are being employed in clinical studies to treat neurological diseases. It is addressed how primary and secondary bile acid production occurs as well as how the regulation of the bile acid pool may vary between the gut and the brain. There is also discussion of the interaction of bile acids with the gut microbiome and their less well-known effects on brain glucose and lipid metabolism, as well as the expression of various bile acid receptors in the brain, their currently understood functions, and the tools available to manipulate them pharmacologically. The dysregulation of the gut microbiota, ageing, sex variations, and potential causative roles in a number of neurological illnesses are also taken into consideration.
