Article 174 of the Amsterdam Treaty of the European Union says “Community policy on the environment […] shall be based on the precautionary principle”. European law, at its highest level, is explicit and uncompromising. As promotion and protection of human health is one of the key motivations of environmental preservation, the provision of the Treaty is good news for public health too. In fact the importance and relevance of the precautionary principle in the health domain has been attracting growing interest.¹ Ministers of health, together with ministers of environment of the Member States in the World Health Organization (WHO) European Region (52 of them in 2004) declared: “We reaffirm the importance of the precautionary principle as a risk management tool, and we therefore recommend that it should be applied […]”.² These are only two of many acts or laws where the precautionary principle is referred to. So what is this principle and why is it important for public health as well as the environment?

Born in the environmental domain in the 1970s, the precautionary principle gained political profile in the 1980s and 1990s, and has attracted the attention of many involved in matters of environmental protection.³ Despite its resonance, there is no unanimously agreed definition of the principle. Quite simply, it is usually taken to state that lack of scientific certainty must not be used as a reason to ignore or postpone preventive or remedial action when there are other good reasons to do so, as has happened many times in the past.⁴ The prescription to err on the side of caution, the “better safe than sorry” approach, may …