Do different design and information content factors influence trust and mistrust of online health sites? Fifteen women faced with a risky health decision were observed while searching the Internet for information and advice over four consecutive weeks. In some sessions their searches were unstructured, whilst in other sessions they were directed to review specific sites, chosen for their trust design elements. Content analysis of concurrent verbalisations and group discussion protocols provided support for a staged model wherein design appeal predicted rejection (mistrust) and credibility of information and personalisation of content predicted selection (trust) of advice sites. Author Keywords Trust, credibility, health, social identity, Internet, computermediated communication. ACM Classification Keywords H3.3 [Information storage and retrieval]: search processes; K4.1 [Public Policy Issues]: computer related health issues.