Nation Tylenol a cancer risk? California considers warning on common painkiller acetaminophen January 22, 2020Jorge L. Ortiz, USA TODAYComments Off on Tylenol a cancer risk? California considers warning on common painkiller acetaminophen Acetaminophen, an active ingredient in popular pain relief medications such as Tylenol and Excedrin, may be considered a carcinogen by California.