Liver disease is an acute or chronic damage to the liver, usually caused by infection which can be viral or non-viral, abnormal changes seen through growth of tumors or tumor-like processes, changes or abnormalities in the metabolic process or naturally through a congenital process. 
Diseases of the liver can also be categorized by the effect. Hepatitis is inflammation of the liver, cirrhosis involves scarring and progressive cell death, stones develop and form blockages, fatty liver and cancer are modification effects from causes that could be related to genetic defects, lifestyle, environment, or other diseases. All these prevent vital functions of the liver and may cause a build-up of damaging substances to the liver itself that could even be a threat to life. Liver diseases can be acute (usually for a short duration) or chronic (commonly lifelong)