Switzerland
Swiss research, published in the medical journal "The Lancet", found that paracetamol -- sold as Tylenol and as a generic, acetaminophen, in the United States -- was not effective at reducing pain or improving movement in patients with osteoarthritis of the knee or hip. The analysis examined 74 randomly-selected trials published between 1980 and 2015 with 58,556 patients who had osteoarthritis. The study did find the prescription drug diclofenac, sold in the U.S. as Cataflam or Voltaren, is the most effective NSAID available. McNeil Consumer Healthcare, the makers of Tylenol, disagree with the study's conclusions.
Sources: CBS News The Lancet