The physician-patient interview is the key component of all health care, particularly of primary medical care. This review sought to evaluate existing primary-care-based research studies to determine which verbal and nonverbal behaviors on the part of the physician during the medical encounter have been linked in empirical studies with favorable patient outcomes. We reviewed the literature from 1975 to 2000 for studies of office interactions between primary care physicians and patients that evaluated these interactions empirically using neutral observers who coded observed encounters, videotapes, or audiotapes. Each study was reviewed for the quality of the methods and to find statistically significant relations between specific physician behaviors and patient outcomes. In examining nonverbal behaviors, because of a paucity of clinical outcome studies, outcomes were expanded to include associations with patient characteristics or subjective ratings of the interaction by observers. We found 14 studies of verbal communication and 8 studies of nonverbal communication that met inclusion criteria. Verbal behaviors positively associated with health outcomes included empathy, reassurance and support, various patient-centered questioning techniques, encounter length, history taking, explanations, both dominant and passive physician styles, positive reinforcement, humor, psychosocial talk, time in health education and information sharing, friendliness, courtesy, orienting the patient during examination, and summarization and clarification. Nonverbal behaviors positively associated with outcomes included head nodding, forward lean, direct body orientation, uncrossed legs and arms, arm symmetry, and less mutual gaze. Existing research is limited because of lack of consensus of what to measure, conflicting findings, and relative lack of empirical studies (especially of nonverbal behavior). Nonetheless, medical educators should focus on teaching and reinforcing behaviors known to be facilitative, and to continue to understand further how physician behavior can enhance favorable patient outcomes, such as understanding and adherence to medical regimens and overall satisfaction.