In a 2009 FDA study, researchers looked at the causes of liver failure in 662 people at 22 U.S. medical centers. They concluded that acetaminophen overdose was the cause in 275, or 42% of cases. But in 48% of cases, the acetaminophen overdose was unintentional.
Most patients (178) survived, although 23 needed liver transplants and 74 (27%) died. Over the six-year study period, the incidence of liver failure caused by acetaminophen overdose grew alarmingly, from 28% to 51%.