A fever reducing painkiller known for it's liver toxicity when taken in semi-large doses, also known as
APAP.
It's found in pretty much any drug that's popular to get high so they add APAP to prevent abuse. Common drugs include Vicodin/
Lortab 5-500mg APAP/Hydrocodone and
Dextromethorphan hydrobromide cough syrup formulas.
Avoid it if you can.