Healthy adults taking maximum doses of Tylenol for two weeks had abnormal liver test results in a small study, researchers found, raising concerns that even recommended amounts of the popular painkiller might lead to liver damage. In the study, 106 participants took four grams of Tylenol _ equivalent to eight extra-strength Tylenol tablets _ each day for two weeks. Some took Tylenol alone and some took it with an opioid painkiller. Dummy pills were given to 39 others. There were no alarming liver test results among the people who took the placebos. But nearly 40 percent of people in all...