It's not the dosage per pill that's unsafe; it's the concentration over a period of time. Acetaminophen builds up in the system. I'd venture to guess that most

It's not the dosage per pill that's unsafe; it's the concentration over a period of time. Acetaminophen builds up in the system. I'd venture to guess that most acetaminophen/paracetamol users aren't popping Tylenol (etc.) every four hours for weeks at a time. But four Vicodin pills a day, taken over the course of a week or two -- not an unusual dosage for pain relief from major surgery or illness -- will concentrate an extremely large amount of acetaminophen in your system, because acetaminophen is eliminated fairly slowly from the body (and at great cost to the liver). You're probably not going to kill yourself taking that much acetaminophen. I've done it a few times, and I'm still here. But you might do some serious, potentially irreversible damage to your liver. It's sort of like heavy metal poisoning: it takes a lot to get an acutely toxic dose, but a slowly toxic dose can accumulate over time.