The current study posits that messages used to elicit behaviors to help unknown others must present substantial perceptions of a threat and efficacy to be successful. Given that many prosocial helping messages depict a threat to unknown others, the current investigation proposed that anticipated guilt is a motivating force behind individuals' willingness to engage in behaviors to avert the unknown-other-directed threat. Specifically, this study hypothesized that messages which induce substantial perceptions of (a) threat, (b) response-efficacy, and (c) self-efficacy would result in feelings of anticipated guilt that subsequently motivate behavioral intent and, ultimately, behaviors to avert the threat to unknown others and avoid the future guilt that they might feel personally. Brehm's (1966) psychological reactance theory, however, notes that such appeals might result in reactance and thus decrease compliance with a message's prescribed actions. Two research questions were posed to determine (a) whether or not individuals experience reactance and (b) what effect, if any, reactance has on compliance. Additionally, participants' accuracy in forecasting guilt was assessed. The proposed model and research questions were tested by focusing on the topic of bone marrow donation. Participants were assigned randomly to one of three message conditions (control and two experimental messages), completed a questionnaire and returned to complete a follow-up survey 7–10 days later. The data were consistent with the proposed model, and additional findings indicated that participants did not experience psychological reactance and were not accurate when forecasting future feelings of guilt.