Opening stages in medical interviews are important because good doctor-patient rapport facilitates the doctor's tasks in later stages, especially in triadic first-visit interviews where doctors are not acquaintances of patients and companions. Given its importance, the research examines opening stages in the Taiwanese context from two perspectives: discourse components of opening stages and discourse mechanisms of presenting non-acquaintances' identities, especially the companions' identities. By examining 30 geriatric triadic encounters collected in a teaching hospital in southern Taiwan, this research concludes that opening-stage interaction patterns in Taiwanese medical interviews differ from Western patterns in the following ways. Under time pressure, Taiwanese doctors tend to open the interview in a fast pattern that hardly allows verbal participation from the patients. The common practice of presenting non-acquaintances' identities in Western conversation openings is rarely observed in the Taiwanese context. As a result, contrary to the professional norms, most companions' identities are not clarified until they talk in the later stages, such as the pedigree stage, which is the most natural context for revealing their identities. This seeming violation of professional norms, however, can be explained by traditional Chinese interaction norms, and can be remedied by following another traditional norm-using a situational greeting. Further recommendations for Taiwanese medical professionals are also proposed to balance these potentially conflicting needs.