Indiana University-Purdue University Indianapolis (IUPUI) / The reliability of information in health social network sites (HSNS) is an imperative concern since false information can cause tremendous damage to health consumers. In this thesis, we introduce a trust framework which captures both human trust level and its uncertainty, and also present advantages of using the trust framework to intensify the dependability of HSNS, namely filtering information, increasing the efficiency of pharmacy marketing, and modeling how to monitor reliability of health information. Several experiments which were conducted on real health social networks validate the applicability of the trust framework in the real scenarios.