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 & Tylenol (acetaminophen) is one of the most commonly used painkillers. It is safe for kids, during pregnancy, and while breastfeeding. However, just because it is safe, doesn't mean that it The parent compounds of acetaminophen (US market in 1955 in the US as Tylenol and other products) were first discovered in 1886 (acetanilide) and 1887 (phenacetin). These were the earliest synthetic fever Acetaminophen metabolism and factors affecting toxicity. GrepMed