Bile acids are a structurally related group of molecules derived from cholesterol that are widely known for their role as chemical detergents involved in the intestinal absorption and transport of fats and lipid-soluble nutrients (Schonewille et al., 2016). However, bile acids also appear to play as yet poorly defined physiological roles in the central nervous system (Lieu et al., 2014). Surprisingly little work has been done on the physiological roles of bile acids in neurons or the central nervous system (Zhang et al., 1997) despite a wide array of data in model systems and despite the significant therapeutic advantages of bile acids. Bile acids are readily bioavailable via oral, subcutaneous, or intravenous administration, can cross the blood-brain barrier, are relatively nontoxic, and have been approved by the U.S. Food and Drug Administration for human therapeutic use. We review evidence supporting a potentially therapeutic role for bile acids in a number of diverse neurodegenerative conditions. A summary of the studies described below is presented in Tables 1, 2.