Biofeedback is a behavioral method of achieving or enhancing voluntary control of physiological processes. Basic studies indicate that a variety of autonomic nervous system and other internal bodily changes can be modified with the method. It has been shown that specific responses and patterns of responses can be controlled. Biofeedback appears to be a promising method of altering symptoms of psychophysiological and medical disorders, e.g., high blood pressure, vascular changes in migraine, neuromuscular abnormalities, and cardiac arrhythmias. This research has stimulated a renewed interest in the role of behavior and the usefulness of behavioral principles in the etiology, treatment, and prevention of medical disorders. The term 'behavioral medicine' calls attention to this new perspective in medicine.