The concern is that chronic acetaminophen use -- best known as Tylenol -- may be linked to blood cancer.
A new report in the Journal of Clinical Oncology found that those who used acetaminophen at least four days a week over four years had two times the risk of blood cancer.
The risk was not seen with the heavy use of other painkillers such as aspirin or ibuprofen.
Scientists say, even though the risk is relatively small, more studies should be done to prove if there is a cause and effect.
