Considering the two most applied ethical ideologies in science, the Value Neutrality and the Precautionary Principle, the latter is the ethical criterion that best fits the way in which chemistry has been developed and is currently executed. This work begins with a historical description of each ideology and a comparison of their fundamental statutes. After an analysis of the main problems that humanity has experienced through the chemical sciences— massive accidents, environmental pollution and public health problems—an evaluation is made of (...) how chemistry has applied the Precautionary Principle to evaluate every scientific and technological development and thus reestablish new criteria for the remediation and prevention of harmful scenarios to humanity and the environment. The work concludes that chemistry has established a basis for ethical exercise applying the Precautionary Principle, and this is reflected in pragmatic and objective developments as Green Chemistry, remediation and substitution technologies, and in Sanitary and Environmental Regulation. (shrink)