This paper was presented as a technical background paper at the WHO sixth Global Conference on Health Promotion in Bangkok Thailand, August 2005. It describes what we know about the effectiveness of four of the Ottawa Charter health promotion strategies from eight reviews that have been conducted since 1999. The six lessons are that (i) the investment in building healthy public policy is a key strategy; (ii) supportive environments need to be created at the individual, social and structural levels; (iii) the effectiveness of strengthening community action is unclear and more research and evidence is required; (iv) personal skills development must be combined with other strategies to be effective; (v) interventions employing multiple strategies and actions at multiple levels are most effective; (vi) certain actions are central to effectiveness, such as intersectoral action and
interorganizational partnerships at all levels, community engagement and participation in planning and decision making, creating healthy settings (particularly focusing on schools, communities, workplaces and municipalities), political commitment, funding and infrastructure and awareness of the socio-environmental context. In addition, four case studies at the international, national, regional and local levels are described as illustrations of combinations of the key points described earlier. The paper concludes that the four Ottawa Charter strategies have been effective in addressing many of the issues faced in the late 20th century and that these strategies have relevance for the 21st century if they are integrated with one another and with the other actions described in this paper.