Lindsay Lohan has been warned by doctors that she is suffering from liver damage and could face serious health consequences if she doesn't curb her drinking.

The MEAN GIRLS star underwent an emergency appendectomy on 4 January (07), the latest in a long list of medical ailments the young star has suffered in the past few years.

A source tells American publication National Enquirer, "The appendectomy was routine, but what doctors discovered in her blood work was not.

"Lindsay's liver panel shows her drinking is taking a terrible toll on her health. Her liver enzymes are extremely elevated."

The high levels of two particular liver enzymes indicate that some of Lohan's liver cells are damaged and are leaking these enzymes into her blood.

In addition to the raised enzymes, the star is also reportedly suffering from extremely low levels of protein in her liver.

A source adds doctors "couldn't believe she was even walking around".