There is currently much enthusiasm for history as a subject of public interest, an enthusiasm which encompasses health issues. History also has its place in the public understanding of science (PUS). The use of history in public policy-making is being rediscovered, in particular by historians in the UK. AIDS heightened historical awareness, and recent examples of historical impact range from foot and mouth disease to cannabis policy. This paper analyses how and when history has had an influence on policy and why and when it does not. It recognizes that issues of impact may be country-as well as issue-specific. The relationship is more complex than it seems. It urges historians to reflect on their new-found enthusiasm for the policy use of history, and uses theories which analyse the research/policy relationship. Historians do not have exclusive command of their material. Social scientists and the health 'field' also use history; and the arrival of online archives makes it easier for anyone to be an historian. There are locations and pathways by which historians could be involved in policy. But this raises issues as to which historians and which history are to be used.
