At the heart of public health is prevention, which means that altering behaviour needs to be the focus of intervention. This chapter explains how and why commercial brands can contribute to public health. It shows how successful behaviour change campaigns can use the best of the marketing resources, whilst appealing to NGOs, governments and solid science. The chapter looks at motivations like peer-pressure, disgust and using play to create a routine as an attempt to find better solutions to handwashing and sanitation promotion for children in schools. Brands on a mission do not simply react to consumers' existing behaviours and desires. For brands to affect large enough numbers of people with relatively small behavioural changes, the best strategy is likely to focus on the middle of the pyramid. As public health leaders recognise the genuine contribution of brands, marketers will have an easier time building processes and partnerships to change behaviour for the better and over the long term.