At the WTO, the precautionary principle/approach is considered as a protectionary mechanism, i.e. and alleged justification for potentially WTO-illegal trade restrictions. This article presents a survey of some pronouncements of the WTO's Dispute Settlement Body including two case studies at opposite ends of the spectrum with regard to the operationalisation of the PP. The Cartagena Protocol on Biosafety has gone further than any other multilateral environmental agreement in specifying the application of precaution. It regulates the measures a member country may take in order to limit or ban the importation of living modified organisms such as seeds or GM commodities. On the other hand there is the Codex Alimentarius that is the WTO's reference point for food safety. Although it has discussed precautionary measures extensively, consensus looks unlikely here in the near future. We shall limit our discussion of the Codex to environment-related food safety, specifically GM food.