According to HON, 24% of the e-patients use the Internet to search for information about their health at least once a day (and up to 6 times per day)! It is difficult to prevent them to consult irrelevant or unreliable information in health forums, however it is possible to develop innovative tools to highlight quality information in these forums. To do this, we will develop in the multidisciplinary project called Patients Mind, new (semi)-automatic tools for e-patient, associations and health professionals to use the more and more massive data issued from health forums, to enable dynamic and interactive knowledge discovery. In this talk, we will particularly focus on trust issues.