Some doses can contain as much as 1,000 mg, and it can be easy to over-shoot the 4,000 mg target. For instance, one pill of Extra Strength Tylenol contains 500 mg of acetaminophen. One dose is two pills, upping the intake of acetaminophen to 1,000 mg per serving. The warning label says a person can safely take 2 caplets every 6 hours and no more than 6 in 24 hours – that is 3,000 mg.