Objective: To develop and pilot test an integrated Cardiac-Diabetes Self-Management Program (CDSMP) incorporating telephone and text-message follow-up. Methods: A pilot study using randomised controlled trial is conducted in the coronary care unit (CCU) in a Brisbane metropolitan hospital in Australia to collect data on patients with type 2 diabetes admitted to CCU. The main outcomes included self-efficacy levels, knowledge, and quality of life. Results: Initial results reveal that patients with diabetes admitted to the CCU in the experimental group did improve their self-efficacy, and knowledge levels. Previous research has identified two important user reactions to Internet-based health behaviour interventions: users trust in an intervention and the extent to which users respond to the intervention as if it were a person (e.g. anthropomorphically). The aim of this study was to examine how these user reactions might be linked to users' engagement with five specific design features of the 'Internet Doctor', an Internet-based intervention to promote the self-care of cold and 'flu symptoms. The five design features were: social context and support; visual appearance; credibility; tailoring; and usability. Twenty six adults aged 18 to 63 participated in 'think-aloud' interviews. Inductive thematic analysis and techniques from grounded theory were used to identify recurring patterns within the data. Three user reactions were identified: users' trust of the 'Internet Doctor'; users' anthropomorphic responses to the 'Internet Doctor'; and users' preference for human involvement in their healthcare. These reactions appeared to be linked to differences in user engagement with four of the five design features (social context and support; visual appearance; credibility; and tailoring). For example, some users who trusted the 'Internet Doctor' expressed positive views of social context and support features (e.g. a question and answer format that was analogous to face-to-face dialogue; information about the 'real' doctor behind the advice) -using them as justification to trust the website's diagnosis and advice. In contrast, participants who expressed a desire for human interaction and were aware of their own anthropomorphic responses to the 'Internet Doctor' were uneasy about features that provided social context and support. Different user reactions were hence associated with different types of engagement with the same design feature. The implications of these findings for the optimal design of Internet-based health behaviour interventions will be discussed. Psychology, University of Evora, Evora, Portugal and 2 Psychology, Instituto Piaget -ISEIT, Almada, Portugal.