At about 4 pounds the liver is the largest gland in the body and the largest abdominal organ. It serves many functions, contributing to the digestive, endocrine and circulatory systems.
You only get one liver. Yes it has the ability to repair itself. However, a number of things can damage it beyond its ability to self-repair.
Alcohol damages liver cells. The more alcohol you drink, the more damaged liver cells are replaced with non-functional connective tissue. In heavy drinkers, the connective tissue continues to infiltrate the liver until it's bloated and unable to function. This condition is called cirrhosis, a disease that frequently ends in a painful death.
Tylenol can be damaging on your liver as well, especially when mixed with alcohol. To be safe, never take Tylenol when drinking or to combat a hang-over.
The liver is the only internal organ that will completely regenerate itself if partly damaged. Up to 25% can be removed and within a short period of time it will grow back to its original size and shape. That is if the remaining liver is healthy!
Glands involved in digestion
Organs that clean the blood