The increasing pace and impact of technological change in the world underline the growing need for taking due precautions. In this essay the author reviews a number of cases over the past 2 centuries where new technologies have been introduced too rapidly with too little attention to possible consequences and avoidable damage to health or the environment has been caused. The author goes on to discuss the precautionary approach to new technology, and urges more widespread use of it. He underlines the importance of 4 key points: (1) technology must not be demonised as the enemy - wise use of technology and technological solutions are themselves part of a precautionary approach; (2) a concern for social and environmental justice must be part of a broad precautionary approach - innovations which may potentially benefit one group while putting other groups at risk are very problematic; (3) we must safeguard the public realm and its ability to weigh up proposed innovations and new processes dispassionately - the privatisation of regulation and management of safeguards is very dangerous; (4) innovation and the management of precautionary safeguards are too important to be left to experts or governments alone - there must be sufficient public understanding and support for the introduction of new technologies with all the risks they may involve if public confidence is not to be eroded and greater restrictions imposed. The precautionary approach does not claim to be the answer to all issues concerning the wise use of new technologies. But it does point the way to how we can use public policy frameworks and processes to guide and constrain technological developments in the most appropriate way, and avoid some of the worst possible outcomes. At a time of accelerating technological change and overwhelming human dominance of the natural environment it is vital that we make wise use of this approach.