Could you tell me what happen if i use tylenol with other medicine that contain acetaminophen?

Don't exceed 3000: You have to be very cautious because Acetaminophen overdose can be silent until lots of damage is done to your liver. You should not exceed 3000mg of Acetaminophen in any 24 hour period. It used to be 4000mg, but studies have shown that damage can occur at that level if over a long period of time for things like chronic pain. If you have been exceeding that routinely, get your liver checked!