The "precautionary principle" is one of the most contested principles in the debate on the new EU chemicals legislation. The purpose of this paper is to operationalise the principle and to investigate the consequences of its application. Five core elements of precautionary management of chemicals are derived and traced in Swedish policy and legislation through history. It is shown that precautionary measures were required as early as the eighteenth century. The conclusion is drawn that these measures in Sweden seem to have promoted sustainable development from both an environmental and a socio-economic point of view.