NASH is an acronym that stands for Non-Alcoholic SteatoHepatitis. It is the most severe form of non-alcoholic fatty liver disease (NAFLD), and is characterized by the presence of an abnormal accumulation of fat in the liver. As NASH evolves, over time it can result in excessive scarring in the liver (fibrosis), a natural response to injury which can lead to liver cirrhosis or liver cancer.
This video by by The NASH Education Program describes why NASH is becoming a public Health Issue.