PDF] Evidence that Increased Acetaminophen use in Genetically Vulnerable Children Appears to be a Major Cause of the Epidemics of Autism, Attention Deficit with Hyperactivity, and Asthma Semantic Scholar Is Tylenol Safe During Pregnancy? Understanding Risk Factors Seeking Health Figure 1: CMAJ Acetaminophen, also known as Tylenol, is used to help with pain & to reduce fever. However, taking too much acetaminophen can be harmful to the liver which filters out toxins & Researchers are studying a possible link between acetaminophen (Tylenol) use during pregnancy and higher autism or ADHD risk. It may lower glutathione, an important antioxidant for brain development.