Audiotapes were made of 140 visits to the offices of family physicians by patients with acute or chronic problems. The tapes were analysed using Bales Interaction Process Analysis to identify interviews which were patient-centred: interviews in which the physician was supportive and encouraged the patient to express himself and in which the patient did express himself and offer suggestions. Instructions about medication were also classified. Four patient factors-age, sex, marital status, level of education-were noted and the relationship between these factors and the nature of the doctor-patient interaction was assessed. Physicians were more likely to ask elderly patients about their drug-taking in the past, but showed less positive rapport towards them. Older patients were more likely to express antagonistic feelings. Female patients expressed feelings while male patients more often presented facts. The physicians actively encouraged such behaviour by expressing themselves more openly with female patients and asking them for expression of feelings. Patients of different educational levels experienced different interviews; the physicians were more likely to appeal to the intellect of a university-educated patient by justifying the drug regimen while offering emotional support to patients with a lower level of education.