The most common cause of atrophy of mammillary bodies (MBs) is thiamine deficiency, which is very common in patients with alcoholic liver disease. The purpose of this study was to look for changes in MBs using brain magnetic resonance imaging (MRI) in patients with acute liver failure (ALF), acute-on-chronic liver failure (ACLF) and chronic liver failure (CLF) of non-alcoholic etiology. Volumes of MBs and caudate nuclei (CNs) were quantified in nine patients with ALF, 17 with ACLF, 18 with CLF and in 24 healthy controls. Volume of these structures was quantified again three weeks after clinical recovery in five patients with ALF who had survived their illness. Volume of left, right and both MBs was significantly decreased (p<0.05) in patients with ALF and ACLF whereas there was no change in patients with CLF, when compared with healthy controls. However CN volumes did not change significantly compared to controls in any of the three patient groups. In the follow-up study significant recovery in volume of MBs was noted compared to baseline values in the ALF patients. We conclude that significant volume loss occurs in MBs in patients with ALF and ACLF of non-alcoholic etiology but not in CLF. This loss of MBs volume recovers substantially in patients with ALF who survive their illness.