For many years, participatory arts projects have been observed to make a significant contribution to the health and well-being of local communities - only for beneficial outcomes to disappear without trace when short-term project funding runs out. At the same time, there has been mounting evidence, commissioned by both arts and health bodies, to show that creativity and the arts do indeed make a significant difference to people's health and well-being and to how they feel about, and interact with, their neighbours. What can be done to build on and develop the evidence base? Particularly in times of austerity, there is also a need to draw on that evidence to develop principles and recommendations for bodies wishing to commission, and artists wishing to lead, participatory or public art initiatives that are most likely to result in sustained benefit to local people and communities. This paper suggests ways in which arts and public health professionals can learn from each other and go on to work more effectively together and with local communities. The paper is based on a qualitative evaluation study of a wide-ranging and innovative initiative, Be Creative Be Well (part of a wider programme, Well London) that nurtured around 100 different small participatory arts projects across 20 of London's most disadvantaged areas. Through analysis of case studies and desk research, the paper presents a summary of what exactly the artist and the creative process bring to a community context and how that can best be supported by policy makers and funders.