The Internet is a novel, rapidly growing means of worldwide public communication. We reviewed all unsolicited electronic mail and other communications from nonmedical individuals requesting medical information over a 12-month period from the physician at 1 established site on the World Wide Web. This site was the only Internet site with a primary focus on cardiac arrhythmias. Seventy unsolicited inquiries were received from 39 patients and 20 family members (the sources of 11 inquiries are unknown) from 20 states, Washington, DC, and 9 foreign countries (locations of 15 inquiries are unknown). Follow-up was obtained in 22 cases. The inquiries concerned cardiological conditions in 67 cases (96%) and cardiac electrophysiologic conditions and procedures in 52 cases (74%). The goals of the inquiries were diagnosis (15), therapy (48), prognosis (1), and patient education (6). On follow-up of 22 cases, the people initiating the inquiries stated that they were reassured (16), consulted a general cardiologist (1), consulted a cardiac electrophysiologist (4), or visited a tertiary care electrophysiology center (1). The increasing use of the Internet by the general public seeking specific medical information for themselves and for their families suggests a widespread, unmet need for objective medical advice. This study demonstrates that the public can choose accurately whom to ask for subspecialty advice in the area of cardiovascular diseases. Professional societies and regulatory agencies should develop physician guidelines for providing medical advice over the Internet.