Believe it or not, Tylenol and the generic versions of it can kill. And the latest research shows now, it's the leading cause of liver failure.

For those in the medical field, it's no surprise that tylenol is actually potentially a very dangerous medication. Part of what makes it so dangerous is that the lay public doesn't know that. And because many believe it to be safe, very often little consideration is given to taking the drug exactly as directed.

Dr. Douglas Dietrich, liver specialist at Mt. Sinai School of Medicine, says, ?People always consider aspirin and ibuprophen to be more dangerous because it can cause bleeding and ulcers but acetaminophen can actually be much more sneakier and cause liver damage in people who least expect it.?

Acetaminophen--the active ingredient in tylenol-- has long known to be a highly dangerous medication if used in amounts above those recommended.

The dosage adds up; if people are on more than one over the counter medicine which contain acetaminophen, like cold remedies, and there are dozens, they could be unknowingly taking too much.

Dr. Dietrich says, ?So how much is to much is the next question. Four grams a day is the maximum anyone should take.?

But many people get much more than this. Now, the latest research shows overdosing on acetaminophen is now the most common cause of acute liver failure in the United States.

It causes at least 42 percent of all cases seen at liver centers. About half of these cases are due to unintentional poisoning as opposed to attempted suicides, the researchers added. More than a third of those who unintentionally overdosed took at least two acetaminophen preparations at the same time

?Half of these were unintentional people just had colds and they were taking medicine for aches and pains,? says Dr. Dietrich.

Overall, about 30 percent of those who develop acetaminophen-related acute liver failure will die.

Those with any kind of liver insufficiency are especially at risk.

?So if you are set up for it it doesn't take very much Tylenol or acetaminophen to put you in liver failure or might kill you or get a liver transplant,? Dr. Dietrich states.

So, when thinking about using Tylenol, one needs to be smart.

?Two Tylenol at one time would be the most that I've taken. I have never exceeded the recommend dose as stated on the bottle,? says Sarah Wheeler, a 28 year old who is careful about using the medicine.

And that's the bottom line to any medication.

Overall 662 patients treated for liver failure were studied. The average dose taken was 24 grams--the equivalent of 48 extra strength tablets.

The unintentional overdoses were seen in those who tended to be older, taking several medications containing Tylenol, on other medicines for pain and also used narcotics and alcohol, all setting up liver insufficiency, making the liver more susceptible to Tylenol.