In the United States, the leading cause of cirrhosis is chronic alcoholism. Alcoholic cirrhosis usually occurs after a decade or more of heavy drinking, although the amount of alcohol that results in damage to the liver varies among individuals. Some people who drink occasionally (social drinkers) may also develop cirrhosis. The liver breaks down alcohol into highly toxic chemicals, some of which trigger inflammation that eventually destroys liver cells.

The second most common cause of cirrhosis is chronic hepatitis B and hepatitis C, both of which cause inflammation of the liver that can lead to cirrhosis. Hepatitis B is most likely the most common cause of cirrhosis worldwide, but is less common in the United States. Hepatitis C is a major cause of cirrhosis in the United States. Infection with hepatitis B or C slowly damages the liver over time. About one in five people with chronic hepatitis C eventually develops cirrhosis.

Other, less common, causes of cirrhosis include:

• Autoimmune hepatitis. A liver disease in which the immune system attacks liver cells. This causes inflammation of the liver, which may be severe and chronic and result in cirrhosis.
  
  
• Nonalcoholic steatohepatitis (NASH). Inflammation and excessive fat buildup in the liver that is not associated with alcohol use. This can lead to inflammation and the development of scar tissue.
  
  
• Inherited diseases. These include diseases that cause high levels of certain minerals to accumulate in the liver, such as Wilson's disease (which causes copper buildup) or hemochromatosis (which causes iron buildup). Cystic fibrosis (a chronic disease characterized by the buildup of thick sticky mucus in the lungs and digestive tract), glycogen storage diseases (which hinder the body's use of sugar) and and alpha 1-antitrypsin deficiency (a disorder in which the liver produces an abnormal amount of a protective protein) can also lead to cirrhosis.
  
  
• Blocked or inflamed bile ducts. Certain diseases, such as primary biliary cirrhosis and primary sclerosing cholangitis, can cause bile ducts to become inflamed, blocked or scarred. Bile ducts transport bile (which is produced in the liver) to the gallbladder and small intestine. There is chronic inflammation and eventual scarring of the biliary system with subsequent liver cell damage and cirrhosis. Primary sclerosing cholangitis can also lead to bile duct cancer.
  
  

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• Parasitic infection. Infection with schistosomia, a parasite that occurs mainly in tropical countries, may lead to liver damage and result in cirrhosis.
  
  
• Cardiac cirrhosis. This type of heart failure can lead to liver congestion or damage.
  
  
• Prolonged exposure to toxins. People who are exposed to environmental toxins, such as arsenic, face a higher risk of developing cirrhosis.
  
  
• Idiopathic causes. In some cases, the cause of cirrhosis cannot be identified.

In general, men develop cirrhosis more often than women. However, women who drink heavily have a higher risk for cirrhosis than men.