Tylenol How toxic is it? Usually Non Toxic Mildly Toxic Highly Toxic Acetaminophen is the leading cause of acute liver failure in the United States. Contact the Washington Poison Center if you or another person has ingested too much acetaminophen (Tylenol(R)) Call 1 (800)-222-1222 Chat with a Poison Specialist Common brands & formats Tylenol Non-aspirin pain reliever Nyquil Dayquil Many generics Tablets Liquid Capsules What to do If ingested Symptoms: can range from mild upset stomach to liver failure and death. What to do: Contact the Washington Poison Center to assess