For most healthy adults, the usual limit for Tylenol Extra Strength (500 mg acetaminophen) is 1,000 mg (2 tablets) per dose, and no more than 3,000–4,000 mg total in 24 hours, depending on your overall health and what your own doctor or the package label says. Going above this, or using these doses if you have liver disease, drink a lot of alcohol, or take other medicines with acetaminophen, can cause serious and sometimes fatal liver damage, so you should always follow the package directions and talk to a clinician or pharmacist if unsure.

If you have already taken more than the recommended amount, feel very unwell, or are not sure how much you took, contact emergency services, poison control, or go to an emergency department immediately, even if you feel okay, because acetaminophen overdose can initially have mild or nonspecific symptoms but still seriously injure the liver.