Mueller M, et al. – This randomized controlled pharmacodynamic study was designed to elucidate molecular mechanisms of ursodeoxycholic acid (UDCA) in regulating endoplasmic reticulum (ER) homeostasis, apoptosis and oxidative stress in morbidly obese patients. The clinicians proposed that in non-alcoholic fatty liver disease (NAFLD) patients, UDCA treatment had ambivalent effects. UDCA's cytoprotective properties potentially changed the apoptotic threshold as reflected by absent induction of pro–apoptotic triggers while increased SAF–scores and elevated CHOP levels could be disadvantageous in the UDCA treated cohort. Among NAFLD patients, UDCA treatment failed to improve the oxidative stress status.