Despite the increasing prevalence, microblogging users are likely to face great challenges in assessing the credibility of health information due to the user-generated nature of content and length restriction on each microblog post. In this study we aim to explore how microblog users assess the credibility of health advice in terms of microblog posts. By incorporating the Elaboration Likelihood Model and Protection Motivation Theory, we theorize that users’ self-efficacy expectation of health actions recommended in a microblog post and their perception of health threat induced by the post can influence their elaboration processes of credibility assessment. As a study in progress, specific design of a controlled laboratory experiment to test the proposed hypotheses is included. Upon completion, this study can potentially provide important theoretical implications in the areas of online health information, microblogging and credibility literature.