The health care sector is quickly exploiting Information and Communication Technologies towards the provision of e-health services. According to recent surveys, one of the most severe restraining factors for the proliferation of e-health is the (lack of) security measures required to assure both service providers and patients that their relationship and transactions will be carried out in privacy, correctly, and timely. A large number of individuals are not willing to engage in e-health (or are only participating at a reduced level) simply because they do not trust the e-health service providers' sites and the underlying information and communication technologies to be secure enough. This paper considers privacy and security issues and challenges for e-health applications.