The active ingredient in Tylenol, acetaminophen, had been known to have anti-fever and anti-pain effects since the end of the 19th century, but no drug company saw fit to manufacture it until McNeil Consumer Healthcare began marketing Tylenol Elixir for Children in 1955 as a safer alternative to aspirin.

Johnson & Johnson acquired McNeil in 1959. In the 1960s J&J pushed Tylenol forcefully after aspirin was associated by an Australian pediatrician named Reye (pronounced "Rye") with a very rare, potentially fatal condition involving the liver and ultimately the brain of infants and children who, Reye found, had been treated with aspirin in response to upper respiratory infections.

Acetaminophen is not as benign as Tylenol's slogan, "Nothing's safer," alleged (and aspirin may not be as dangerous as the pharmaco-medical establishment now alleges). Acetaminophen poisoning has become the leading cause of acute liver failure (ALF) in the U.S. Some of the cases are suicide attempts, some are unintentional.

Many consumers don't realize they're overdosing on acetaminophen because they don't know it's an ingredient in hundreds of over-the-counter drugs -Nyquil, DayQuil, Theraflu, Excedrin, Coricidin D, Triaminic, Dristan, Midol, Pamprin, etc.- and prescription painkillers, including Vicodin and Percocet, the two most widely used.

More
http://counterpunch.org/gardner06102006.html