Recently, John Mandrola et al. established the tenets of medical conservativism. We endorse this approach to patient care, and we believe that, in order to have this perspective incorporated into medical reasoning, the foundations for being medical conservatives should be taught since medical school. In this Perspective, through an analogy between medicine’s and criminal law’s approaches to uncertainty, we suggest that the precautionary principle of in dubio pro reo could be adapted to medicine as a decisional strategy for medical conservatives. This principle would represent a cognitive and decisional filter that allows physicians to counterbalance the currently widespread propensity toward interventions with a conservative and precautionary attitude.