Pharmaceutical agents are prescribed to produce a therapeutic effect, but safety concerns require constant attention to the benefit:risk relationship inherent in their use and the needs of the individual patient. Such calculations involve assumptions about the likely tolerability of harm, in that greater safety risks may be acceptable for use of a lifesaving drug, compared with those acceptable for an agent providing only improved "quality of life.” Making such assumptions is an activity integral to the bedside clinician’s role, is done during many (perhaps most) patient encounters, and is often undertaken with inadequate information. The historical mandates for regulatory agencies, such as the Food and Drug Administration (FDA) in the United States, have evolved over the past decades to include an intense focus on drug safety. Communicating information about medicinal risk remains a major responsibility for the FDA and similar bodies, but the initiatives undertaken have had variable, and often limited, effectiveness in penetrating the physicianpatient interaction. Barriers to the successful communication of safety-related issues include the myriad of influences on and within the FDA, the time constraints on physicians involved in clinical practice, and the methodologies used to share information about both established and new drugs. Current efforts to assess the effectiveness of regulatory efforts at risk communications should lead to changes in the approaches used and, ultimately, improvement in the safe use of both new and established drugs.