Whether true or false, media information shapes people’s thinking. False information trigger beliefs which could compromise health behaviour. In this intervention study, the effect of controversial messages on 91 young participants’ judgement of health issues was tested. Held opinions about health-related issues were assessed before, after and one week after viewing a controversial TV-interview. Using pre-interview opinions for baseline, changes in judgements were assessed immediately after and one week after the interview. At both times, the opinions differed statistically significantly from baseline (p < .001). The relationship between opinions immediately- and one week-after viewing the interview was statistically significantly stronger (p < .001) than their association with the baseline. The results provide evidence for immediate change in judgment resulting from controversial information and demonstrate that the change persists for at least one week. The findings can be explained based on the schema theory and suggest that controversial information could have powerful impact on subjective judgement. Consequently, young people need to be educated in health issues and in the evaluation of media information to enable them to make the right choice when the need arises.