Under current U.S. law, physicians may prescribe drugs and devices in situations not covered on the label approved by the Food and Drug Administration. Those supporting this system say that requiring FDA approval for off-label uses would unnecessarily impede the delivery of benefits to patients. Patients do benefit from off-label prescribing that is supported by sound scientific and medical evidence. In the absence of such evidence, however, off-label prescribing can expose patients to risky and ineffective treatments. The medical community and federal authorities should more actively promote patients' interests in receiving beneficial off-label treatments. To exercise responsible self-regulation, members of the medical community must determine whether available evidence justifies specific off-label uses and must promote information-gathering when the evidence is inadequate. Physicians should also discuss with patients the uncertainties accompanying off-label uses. Federal authorities should more closely monitor the effects of off-label prescribing and adopt other measures to reduce harm and enhance benefits produced by off-label prescribing.