Acetaminophen, found in Tylenol and other prescription and nonprescription products, can lead to liver failure if taken in excess. This year, an advisory panel of the Food and Drug Administration recommended lowering the maximum allowable dose, making certain products containing acetaminophen prescription only and banning others. Particularly worrisome is the number of people who take the drug unknowingly in cold medicines and other preparations. The FDA website (fda.gov) has more details. So does your doctor.