Positive emotional appeals can be an important, if often underutilized, component in health campaigns. Research reviewed from advertising, marketing, health communication, and social influence demonstrated how campaigns can promote risk-reduction behaviors by focusing on positive incentives, highlighting positive outcomes, and evoking positive feelings toward the health-related behavior. People who feel good during and after exposure to a health message tend to have favorable attitudes toward the message, which in turn establishes more open, rather than resistant, attitudes toward the issue or risk-reduction behavior promoted in the message. Along with influencing behavior via attitudes, positive affect can have a direct impact on behavior or intention. As suggested by broaden-and-build theory, positive affect broadens attention and thinking processes, increases openness to information, and helps form beliefs that the behavioral change promoted in the message is possible. Relatedly, positive affect tends to activate approach-oriented behaviors through the function of the behavioral activation system. Two primary strategies have demonstrated efficacy at promoting positive feelings: the use of gain-framed appeals and evoking the core relational theme of happiness. Gain-framed appeals emphasize the rewards obtained by following message recommendations and can boost behavioral adoption, particularly of proscriptive behaviors, by highlighting positive outcomes and goal congruency. Happiness occurs when people believe they are making progress toward realizing their goals, and messages can be created to induce positive feelings like happiness by focusing on self-efficacy, response efficacy, and perceived benefits. Positive message appeals are especially useful for counteracting the potential drawbacks of traditional negative appeals in that they can reduce message fatigue, gain attention, and attenuate psychological reactance. Challenges for future research include increasing efforts to systematically understand how and when to best utilize the power of positive messages in campaigns. Another related challenge is to examine how positive affect is aroused at a particular stage of exposure to health risk messages, and how emotions (both negative and positive), flow, evolve, and transit from one to another (e.g., fear to relief, anxiety to happiness) during and after message exposure.