PurposeThis paper aims to explore the underlying mechanism whereby information-induced stress, resulting from the burdensome nature, questionable information reliability, misleading content and diffuse characteristics of infodemic pressure, impacts individuals’ online information-related behavior and health-related preventive behavior.Design/methodology/approachWe conducted a cross-sectional survey organized with social media users during the post-pandemic period. Based on the 342 valid responses, structural equation modeling was employed to validate the research model.FindingsThe results substantiate our multidimensional view of infodemic stress, which encompasses dimensions including information overload, uncertainty, diffusivity and insecurity. We found that the infodemic stress contributes to pandemic fatigue, then engenders both negative information behavior and reduced engagement in preventive behavior. Furthermore, infodemic stress has also been found to have a direct positive effect on individuals’ engagement in preventive behavior.Originality/valueThis study introduces the concept of “infodemic stress” and presents a comprehensive framework to capture its various dimensions. This study offers novel insights into the psychological and behavioral repercussions of the infodemic stress transmitted through social media.