Get to Know the Tylenol Toxicity Warning Signs. Breathing Difficulty, Swelling or Rash, Grey Color Stool, or Yellowing Skin are ALL signs of Tylenol/Acetaminophen toxicity and potential liver failure. Even non-drinkers are at risk. By now you have probably heard that Tylenol (or, more specifically, acetaminophen) can damage the liver. In most cases, damage to the liver is thought to occur because of...