Although the scientific literature consists of over 10,000 papers on eHealth, remarkably few applications are consistently being used in the healthcare domain. Numerous reasons for this lack of progression have been noted, one of these being the objection of medical professionals to the introduction of interventions that are supposedly lacking evidence of their effectiveness. A study of existing literature and, especially, literature reviews confirms that there does not yet exist scientific evidence of the effectiveness of eHealth. But, this study also comes across insights in the reasons why scientific evidence is hard to come by and possible future directions for healthcare organisations how to take advantage of eHealth despite the current lack of interventions that are truly evidence-based and for eHealth researchers to build collectively a stronger evidence-based case for eHealth interventions.