There is still a lot to gain in the field of health communication. Mass mediated health campaigns often do not have a direct effect on health behavior, but conversations about health issues in an informal setting, such as with partner, family and friends appear to play a significant role here. However, we do not know much about factors that influence the occurrence and the effects of such interpersonal health communication. Therefore, four empirical studies are discussed in this dissertation.

First, the factors that influence whether, when, with whom and how people talk about health issues were investigated qualitatively. The results show that interpersonal health communication is not one general type of behavior, but instead consists of several subtypes of behavior, each of which differs in its influencing factors.

Subsequently, two health message types were investigated in their ability to trigger conversations: the complex message and the narrative message. The complex message, at least when personally relevant, appeared to be unsuitable for achieving this goal. The narrative message, aimed at college students and regarding the health theme safe sex, appeared to be a promising strategy to trigger conversations.

In the fourth study, actual conversations about safe sex in response to this message were therefore analyzed. The conversations positively influenced college students’ safe sex-related intentions. In the conversations, safe sex was mainly discussed positively and casually, for instance by exchanging anecdotes. Moreover, the conversations exposed behavioral patterns, providing valuable information on, for instance, attitudes and social norms regarding safe sex.