In March 2011, the Journal made an error—on the cover. It portrayed a short, smooth, and vertical staff with two intertwined snakes, the Caduceus, as the ancient symbol of medicine (above left). Four months later, a letter to the editor (1) pointed out that the correct symbol is instead the diagonal, rough-hewn, single-snaked staff of Asclepius (above right). This mistake began in the late 19th century. One of the earliest medical misuses of the Caduceus was by John Churchill, a London publisher of medical books (2). American publishers followed, and in 1902 the U.S. Army Medical Corps adopted the Caduceus as its insignia. Many others, including the U.S. Public Health Service, were to follow. Corrections seem to have had little effect. In fact, in reviewing the history of this error, we found more than 30 articles in the literature that discuss the mistaken use of the Caduceus instead of the staff of Asclepius. This discussion dates back to a 1928 article in the Canadian Medical Association Journal that describes the history and inaccurate swapping of these two symbols (3).