The real danger of Tylenol isn't autism it's liver failure. Acetaminophen, the active ingredient in Tylenol and many cold and flu medications, is one of the leading causes of liver failure Annals of B Pod Acetaminophen Overdose Taming the SRU Is Tylenol Safe During Pregnancy? Understanding Risk Factors Seeking Health Tylenol lowers glutathione, which is why it can cause liver failure. Low glutathione can cause many serious health problems that can vary from person to person. Finding out if you have genes Tylenol and Alcohol: The Dangers of Polydrug Abuse