Purpose - This paper considers some implications of recent developments relating to patient safety for understandings of trust in health care contexts. Design/methodology/approach - Conceptual analysis focusing on patients' trust in health care providers and health care providers' trust in patients. Findings - Growing awareness of the scale of the problem of iatrogenic harm has prompted concerns that patients' trust in health care providers may be threatened and/or become inappropriate or dysfunctional. In principle, however, patients' trust may be both well placed and compatible with current understandings of safety problems and efforts to address these. Contemporary understandings of patient safety suggest that, to be deemed trustworthy, health care providers should make vigorous efforts to improve patient safety, be honest about safety issues, enable patients to contribute effectively to their own safety, and provide appropriate care and support after safety incidents. Patients who trust health care providers need not be ignorant of patient safety problems and may be vigilant in the course of their care. Iatrogenic harms do not necessarily reflect breeches of trust (not all such harms are yet preventable), and patients who are harmed might in some circumstances appropriately forgive and resume trusting. Health care providers may feel vulnerable to patients in several respects. From their perspective, trustworthy patients will act competently to optimise the outcomes of their health care efforts and to preserve health care providers' good reputations where those are justified. Providers' trust in patients may strengthen patients' trust in them and facilitate safety improvement work. Originality/value - Shows how, in principle, trust can be compatible with current understandings of patient safety issues and may enhance efforts to improve patient safety.