N-acetyl-p-benzo-quinone imine (NAPQI) is a toxic metabolite of paracetamol (acetaminophen) formed in the liver, particularly when paracetamol is taken in excessive doses. It is clinically significant because NAPQI can deplete glutathione levels, leading to hepatotoxicity and potentially acute liver failure. A key association is its role in paracetamol overdose, where early recognition and treatment with N-acetylcysteine can mitigate liver damage.