A review is presented of factors that have been investigated on their relevance in mass media communications that are specifically designed to alter health and safety related behaviours of the recipients. While alcohol consumption is a major concern in this paper, the evidence regarding the effective use of mass communications for the modification of other health and safety habits has also been incorporated. Specific topics include the choice of yardstick of effect, study methodology and the strength of conclusion this permits, as well as the dependency of the effect of mass communication upon its four constituent components: the source, the content of the message, the channel of communication, and the characteristics of the recipients. Reference is made to the effect of educational journalism related to the prevention of health problems and to efforts to increase the educational value of traffic accident reports in daily newspapers through the inclusion of information that is potentially helpful to accident avoidance.