In contemporary medicine, it is not always obvious whether the acceptance of a benefit constitutes a conflict of interest. A particular area of controversy has been the impact of small gifts or other benefits from pharmaceutical companies on physicians' behaviour. Typically, in such cases, the gift is not an explicit reward for cooperation; the physician does not perceive the gift as an attempt to influence his or her judgement; and the reward is relatively minor. Under these circumstances, physicians are generally (...) of the view that acceptance of gifts will not affect their behaviour, notwithstanding findings from social psychology and neuroscience that the impact of gifts is often unconscious, shaping action without a person's awareness. Here, we draw on traditional texts of Jewish law pertaining to the prohibition of taking a gift to illustrate recognition by the ancients of unconscious conflicts of interest, and their approach to dealing with the problem. (shrink)