This article examines the role of medical interpreters in structuring interaction between physicians and their patients. Through a detailed analysis of interpreters' involvement in the history-taking part of medical consultations, it is demonstrated that their participation in this activity is organized by their understanding of its goals rather than by the task of translation alone. Specifically, the different ways in which interpreters participate in history taking display their orientation to obtaining from the patient and conveying to the doctor medically relevant information about the patient's symptoms - and doing so as effectively as possible. Medical interpreters are found to share the physicians' normative orientation to obtaining objectively formulated information about relevant biomedical aspects of patients' conditions. Thus, far from being passive participants in the interaction, interpreters will often pursue issues they believe to be diagnostically relevant, just as they may choose to reject patients' information offerings if they contain subjective accounts of their socio-psychological concerns.