Advanced Information and Communication Technologies (ICT) solutions are the key instrument to enable modern integrated care. They are not limited the traditional boundaries. Moreover, their aim is to provide medical care at the right point, in the right manner, at the right time without technological, institutional boundaries or integration issues, esp. for comorbidity treatment cases. Open digital ecosystems enabled by eHealth platforms can help to create a prospering eHealth environment. However, the creation of digital ecosystems in the health care domain is an ambitious task. The conditions how an open system can be achieved are often consented in complex projects, but they are not often scientific questioned. Conducting an action design research process, the paper contributes 13 guidelines for implementing eHealth platforms by reflection of the work in an EU-funded infrastructure project, which can be used as input for further research to provide generic guidelines for eHealth ecosystem projects.