Researchers led by Dr. Li Zhou from Partners HealthCare System Inc in Wellesley, Massachusetts, reviewed the electronic health records of 23,750 adults treated at two hospitals during the summer of 2010. That included 14,411 people who took any acetaminophen during their stay. Based on calculations from the electronic records, Zhou's team determined that 955 of those patients were given over 4 grams of acetaminophen in a 24-hour period, most on more than one occasion. More than 20 percent of elderly people, and close to that many patients with liver disease, were given over 3 grams in a day.