Some of his anatomical and physiological observations were accurate - for example, he proved that urine was formed in the kidney (as opposed to the bladder, which was a common belief). His most important discovery was that arteries carry blood, although he did not discover circulation” (Galen, BBC). His experience in treating gladiator injuries also contributed to his fame. For example, he cleaned wounds with wine and sponges to prevent infections; and if the wounds were too large, he would provide stitches. The Hippocratic bench was also an important aspect of Galen's medical practice, it was a bed used to stretch the patient's body and the tension helped align broken bones. He also discovered the sedative effects of opium and alcohol.