Conflicts of interest are rife in all areas of human endeavor, including medicine. Dealing with them is often difficult, because various disclosure remedies are sometimes too weak, while explicit prohibitions against participation in certain forms of research could block the needed synergies between scientists who work in universities, government, and industry. The situation is made still more difficult, because any effort to control one set of conflicts will necessarily generate another in its stead, as is well captured in Juvenal's famous question, "Who will guard the guardians?" That problem is more acute today, because many of our social watchdogs are in fact complex organizations that are rife with their own internal conflicts of interest. The problem is acute for the FDA, for example, which so fears the release of harmful drugs that it often keeps beneficial ones off the market. The problem can also arise in connection with the review of medical research by major journals, which is well illustrated by the recent effort of the New England Journal of Medicine to attack a Vioxx study it published in order to protect its own reputation.