An enlarged liver (called Hepatomegaly) usually indicates some form of liver disease, although a diseased liver can also be normal-sized or even shrunken.

The liver is the largest and most massive internal organ of the human body. The mass of a healthy human liver is approximately 1.2-1.5kg (approximately 2.5-3.0lbs).  The liver's mass comprises one-fortieth to one-fiftieth of an adult's total weight and one-eighteenth of the body's weight during infancy. Located in the upper-right part of the abdomen behind the ribs, the liver is dark red-brown organ with a soft, spongy texture that is nearly 15cm (6in) thick and consists of two main overlapping lobes (right and left).

The liver's size is a clue as to how important its role is in fulfilling the body's metabolic needs and maintaining daily homeostasis. The liver performs more than 500 different functions in the body.  As part of the digestive system, the liver aids the body in fat digestion, manufactures and secretes bile, regulates the levels of chemicals in the blood, synthesizes proteins, filters waste products from the bloodstream, and receives nutrient-rich blood from the gastrointestinal tract and either stores or transforms these nutrients into chemicals that are used elsewhere in the body.

Causes and Development
The liver possesses the unique ability to regenerate cells that have been destroyed by some short-term injury or disease. However, long-term repeated damage to the liver may result in permanent irreversible changes or damage. Infections or diseases of the liver, often caused by excessive alcohol consumption, may hinder the organ from performing its many essential functions.

Signs and Symptoms
An enlarged liver usually causes no symptoms, and since the liver does not contain any nerves, pain does not emanate from the liver itself. However, if the enlargement is extreme, it may cause abdominal discomfort (by pressing against other organs and nerves) or a feeling of fullness. If the enlargement occurs quickly, the liver may be tender to the touch. When performing a physical examination, a doctor can usually estimate the size of the liver by feeling whether it extends below the level of the ribs.