[JshWright]

Overdosed on NyQuil? How much NyQuil did he take?

I have no idea how big a typical bottle of NyQuil is, but assuming it's somewhere in the ballpark of 10oz (we'll call it 300ml to make the math easy). NyQuil has 325mg/15ml, so our hypothetical 10oz bottle has ~6,500mg in it. That's certainly a respectable dose of Tylenol, but it's not likely to be fatal in a couple hours for an average sized adult...

[carbocation]

I'd guess that the problem was excessive sedation due to the antihistamine, rather than acute liver injury from acetaminophen toxicity.