E-health is an emerging field on the intersection of medical information technologies, public health and business, referring to health services and information delivered or enhanced through the Internet and related technologies. Portal technology, allowing services to be accessible over the Internet is a perfect tool for providing e-health services. The use of portal technologies has had deep influence on the architecture of the whole e-health system, both regarding new subsystems and older ones which we want to integrate with the portal. Portals provide new possibilities for creating novel types of e-health applications as well. In this paper we provide a brief overview of e-health systems and portal technologies, and present many technical aspects of portal technology application for e-health systems such as the architecture of portal-based e-health systems, graphical user interfaces, access to various e-health systems' resources, personalization, security and privacy.