The notion of ubiquitous computing (ubicomp) has important implications for health care. Ubicomp scenarios involving the rapid communication of information between interested parties assume that health consumers will be willing to place their trust in agents rather than physicians, but are these assumptions reasonable? This article discusses what is known about the role of trust in health care and ways in which the trust relationship has changed with the impact of new technologies. Differences between the current, predominantly web-based environment and that of ubicomp are highlighted in relation to health care. A key point to note is the move away from consumers making their own trust judgments toward a scenario in which these decisions become the domain of intelligent agents.