The liver has an impact on pretty much every part of the body. The liver also, being a kind of jack of all trades, is susceptible to many types of ailments.
The most common illness are the five different viruses of hepatitis A, B, C, D, and E. Hepatitis is an inflammation of the liver due to viral infection. There are other viruses that may hurt the kidney like yellow fever, cytomegalovirus, herpes simplex and others, but hepatitis is the most commonly seen.
The drug acetaminophen and some cancer fighting drugs can have an adverse impact on the liver.
The liver has a great ability to regenerate. Regeneration is very rapid, removal of half of the liver mass can be replaced in one to two weeks.
The down side of any liver damage is that symptoms don't generally show up until there is significant damage.