What sort of problem is an acetominophen (tylenol) overdose or poisoning?

Acetominphen overdos: Although the actual parent drug acetominophen is relatively little toxic, the body (liver) makes a very toxic chemical out of it that can quickly destroy the liver cells. This is or was the most common cause of suicide in great britian. The toxic dose is about 3000 mg and higher, but it is not possible to tell what an individual's toxic dose is. An emergency intravenous medication is available.

Liver failure: Most dangerous result of Acetaminophen poisoning is liver failure leading to severe damage of all system and often to death.