Statements on conflicts of interest provide important information for readers of scientific papers, write David Stuckler, Gary Ruskin and Martin McKee in the Journal of Public Health Policy in a case study of emails exchanged between Coca-Cola and the principal investigators of the International Study of Childhood Obesity, Lifestyle and the Environment. There is now compelling evidence from several fields that papers reporting funding from organizations that have an interest in the results often generate different findings from those that do not report such funding. The authors describe the findings of an analysis of correspondence between representatives of a major soft drinks company and scientists researching childhood obesity. Although the studies report no influence by the funder, the correspondence describes detailed exchanges on the study design, presentation of results and acknowledgement of funding. This raises important questions about the meaning of standard statements on conflicts of interest.