Many activists use scientific evidence to promote social change. Other pressure groups deny or distort scientific evidence to support irrational or religious beliefs. As experts in science communication, where do science centres and museums stand in relation to science-based activist movements? When scientific evidence is used for social change, should science centres “step in” or can they “hold back”? Which competences and strategies are needed during times when active citizen involvement in science is a de facto reality? The speakers – activists and members of pressure groups – will present their points of view on three hot topics: HIV, stem cell treatments, and the environment. Case studies will start a reverse session where activists let us know how they perceive science centre professionals and we will reflect and discuss on how our institutions handle (or don’t handle) activist science.