The precautionary principle had its origin in German environmental law as the basis for protective measures in situations of scientific uncertainty regarding the risk. However, its evolution has made it extends to other areas of law. The transfer of this principle to Spanish criminal law has been primarily based on several court decisions in the field of public health crimes. These decisions have been the basis of an interpretation of the criminal offenses that in many cases, unaware of the limits imposed by legality, harm and minimum intervention principles.