As severe ill and incurable patients can be easy victims of misleading advertising activities for dangerous and non-effective healthcare treatments, the marketing of healthcare services are in many jurisdictions legislations tightly regulated. This article reviews the Danish regulation on marketing of healthcare services to identify which types of advertising activities that are legal. As the legislation only allows healthcare authorities to control the marketing and not the content and quality of the marketed healthcare services, their ability to intervene in serious cases of misleading advertising is limited. Misleading advertising are statements with the purpose to exaggerate or underestimate the effects and risks of healthcare services or to prevent patients from seeking conventional medical treatments. From a public health perspective, there is a need for a common EU legislation for regulation of the marketing of healthcare services as the increasing use of information technologies makes it possible for the providers to access consumers and patients directly across countries and legal systems.