Message framing readily lends itself to marketing communication and advertising persuasion strategies. However, past research yields contradictory and inconsistent predictions as to whether positive or negative frames are more persuasive. This study examines the most appropriate message framing to present to consumers in print advertisements for health care products. Two experimental studies are conducted to investigate the moderating effects of product functions: perceived innovativeness and perceived risk on the processing of framed advertising messages. Findings of Study 1 indicate that messages for familiar products should be framed differently depending on perceived product functions (prevention vs. detection), but gain-framed messages are more persuasive for both new prevention and detection products. Results of Study 2 suggest that a mixed-framed message (combining gain and loss) could enhance message effectiveness only when subjects have prior experience. Similar to the role of product function, product perceived risk is found to moderate the framing effects on message effectiveness. © 2007 Wiley Periodicals, Inc.