I never took more than 3 at a time, usualy 2 though. My friend took 3 for a long time then went up to 4 at a time. 4 a time worried me. I would not suggest that. The bad part about the previous posts advice of no more than 4000mg of tylenol a day is that no one sticks to that unless they are using those pills for their purpose and usualy aren't addicted yet. Everyone I've known that took them daily were addicts. The least I've known people to take is five 10mg a day. That's because addicts usualy get sick off only four 10mg because the amount of hours in a day they are awake. That's the lowest for a person that isn't trying to get high and is active and functional. The deeper addicts take a lot more. A lot more. When I was addicted to them I took 7 to 10 10/650s. Which was less then my addict friends. My boyfriend at the time took 15 to 20 10/650s a day. And...there were people that still took more than that. You basically need to be informed as with any drug. Then. You decide what you want to do knowing the risks your taking. My opinion is, like with most drug use, most people can tolerate the abuse without dieing or long term effects. However. You don't know your bodies limits, so you are taking the chance. I highly recommend having a liver function test at least every six months. Liver failure is the main side effect. That is where the recommended dose comes from. It's been determined that 4000mg is the most your liver are most likely going to be able to absorb and process correctly. Anything more than that becomes toxic. You need to read up on what can happen from that. The worst is it poisoning your liver and it shutting down and you dieing a painful death. Worst case I read, within like 8 hours for having too my tylenol I think. But there are many complications to learn about and also all the other things that can happen other than the liver deal. So educate yourself before you decide.