For many of us suffering occasional aches and pains, reaching for the Tylenol has become almost a reflex. The best-selling over-the-counter pain reliever and its generic copycats are staples in American medicine cabinets. The active ingredient in Tylenol is acetaminophen, a versatile molecule that can cool a fever, soothe a teething baby and dull the sharp joint pains of osteoarthritis.
Now, however, the U.S. Food and Drug Administration is asking some tough questions about acetaminophen. It's a drug that can do serious damage to the liver when used outside prescribed guidelines, and it's not at all clear that the warnings...