The effects of bile acids on chemical and genetic models of Parkinson's disease (PD), which is characterized by the selective loss of dopaminergic neurons in the substantia nigra region of the brain and a resulting tremor, have been reported. Sodium nitroprusside (SNP)-induced cytotoxicity of human dopaminergic SH-SY5Y cells has been used as a model of PD. UDCA was found to dose-dependently (50–200 μM) decrease SNP-related cell death. UDCA reduced reactive oxygen species (ROS), reactive nitrogen species (peroxynitrite and nitric oxide), and helped to maintain intracellular glutathione (GSH) levels. Apoptosis markers including nuclear fragmentation, caspase activation, and cytochrome c release were correspondingly reduced. Inhibiting phosphatidylinositiol-3-kinase (PI3K) and Akt/PKB blocked the favorable effects of UDCA on SNP-induced cytotoxic cell death (Chun and Low, 2012).