[The precautionary principle in preventive actions: considerations on an absence].

The precautionary principle (PP) consists of measures to be taken to avoid harm under serious damage or catastrophe to the environment or human health and scientific uncertainty about its causes and/or incidence. However, PP has not been used to prevent severe iatrogenic harm from actions derived from primary (P1) or secondary (P2) prevention actions in medicine or health systems. This essay synthesizes a proposal for this use, defends its adequacy, and offers four comprehensive, interconnected, and synergistic hypotheses as to why it is yet to occur: (a) such use is very anti-intuitive due to the teleological similarity between PP and prevention and their contextual differences; (b) the future moral expansion of medicine has generated a preventive supremacy that unrestrictedly expands tolerance to P1/P2 iatrogenesis; (c) some of these iatrogenic diseases are anomalies (in Thomas Kuhn's sense) with complex identification and measurement, making it difficult to accept and value them; (d) the following ongoing naturalization of preventive iatrogenesis makes it unthinkable to consider PP for its management in serious cases of doubt, leaving it outside the horizon of preventive medicine and paradoxically making it more necessary.