Accurate and sensitive communication of health care information is essential to effective patient management in the pain clinic, operating room, other health care settings. However, information relating to the health care status of a patient is sensitive and may be embarrassing or damaging if it falls into the wrong hands. Ethical cannons of medicine and statutory provisions have emphasized the obligation of the physician to safeguard patient confidences. However, threats to the confidentiality of medical information abound and are even more significant in our age of instantaneous communication characterized by the growing use of email, facsimile, and the Internet. This article outlines legal issues relating to communication in three key areas of health care law: confidentiality/breach of privacy, informed consent, and defamation. The major principles of the law in these areas are discussed and case studies are used to illustrate key points and give simple preventive strategies to help steer the delicate balance between sharing important healthcare information and protecting sensitive patient information.Key Words. Medical-legal communications; Medical records; Privacy; Confidentiality; Defamation Dr E saw patient XY in the pain clinic of a large referral hospital. XY had previously been seen and treated for reflex sympathetic dystrophy as an outpatient by physicians in a small town several hundred miles away. Dr E wrote a note in the electronic medical record: "It is difficult to imagine how therapy prescribed previously could have any chance of helping XY. In fact, earlier mistakes may have compromised my ability to effectively treat her." D r E may have thought she was protecting herself from malpractice exposure by blaming previous physicians for XY's difficult-to-treat condition. Unfortunately, not only does a comment like this increase the likelihood of malpractice action, but it also exposes Dr E to the risk of a lawsuit for libel initiated by XY's previous physicians.Information in medical records is now read by a multitude of parties. Anything entered into the record should be considered a communication to others. The comment in this medical record is derogatory toward previous physicians. It expresses more than a different judgement regarding a particular clinical decision and goes on to express an opinion about the competence of previous caretakers.This particular case reflects an additional problem. The ability to transmit medical information widely and quickly has never been greater. The use of email, facsimile, and the Internet presents a tremendous opportunity to improve health care by putting complete, accurate, and timely patient data in the hands of practitioners when they need it. However, the rapid dissemination of information has its downside. Whereas old-fashioned paper charts are available to dozens of people who provide care or review medical records for other purposes, an electronic medical record may be accessible to hundreds if not thousands of others. The potential for damage resultin...