Tylenol - Uses, Complications, Recalls and Warnings - Drugwatch.com While Tylenol is relatively safe when taken at the correct dosage, ingesting too much of the drug can lead to serious complications, including liver failure. Tylenol (acetaminophen) is the most popular over-the-counter (OTC) pain relief medication used in the U.S. and around the world. Acetaminophen is the active ingredient in Tylenol and the ...