This paper proposes a critical reading of the precautionary principle, looking further, specifically, some issues that undermine the principle balance as guidelines for making decisions of who is responsible for taking them. Thus, the article is structured in two parts, (i) first we address the theoretical question, developing the concept that in the doctrine, must face at first, taking into account two essential aspects are the implications involved battling the uncertainty scientific fundamental element of the principle; and defense of the thesis that in many cases the stability of the application of the principle involves the selective omission of certain hazards of the situation being analyzed. Furthermore, (ii) we will address an issue that involves the notion of the precautionary principle which is its application in the real plane. In this second part , a description will be compared to the way , from the perspective of the Constitutional Court, has been conceptually addressed the precautionary principle , introducing the applicative section consists of reading , from our point of view, has judicially understood as the scope of the precautionary principle in the local area .