Physician-patient discourse, even same-language discourse, may be viewed as a type of cross-cultural interaction. Inside the US, there is a large and increasing number of adult Third World immigrant patients who do not speak English. For these patients the "cross-cultural" aspect of First World medical practice is underscored by the presence of the medical interpreter, who is herself faced with the task of negotiating both the content of utterances and also the cultural contexts from and into which these utterances are conveyed. Analysis shows that, through variable patterns of how and when utterances are interpreted, the interpreter functions, not as an "ally" of the patient nor as a neutral conveyer of propositions, but rather as a covert co-diagnostician and institutional gatekeeper. As one result, these patients are often seen as "passive" and "non-compliant" by physicians, with consequences for how care is delivered and for their treatment by the institutional State.