More is not more effective when it comes to over-the-counter pain relievers containing acetaminophen, the active ingredient in Tylenol. Consumers who gobble four pills at once thinking they will get faster relief are risking serious liver damage or even death, doctors warn.

That’s because acetaminophen at levels higher than 4,000 mg per day – the equivalent of eight extra-strength tablets – can build up in the liver, causing toxicity that may require a transplant or, in rare cases, lead to death. Because many flu and sleeping medications contain acetaminophen, as do some prescription pain relievers, it’s important for consumers to read labels and calculate how much they have taken. For people whose livers are impaired by hepatitis or who are daily or heavy drinkers of alcohol, the maximum safe dose is about 3,000 mg