This article addresses and discusses situations in which untrained interpreters deal with medical terms. The author shows that the different ways in which this is done can be seen in relation to the particular speech situation, the pre-existing action systems between the interpreter and the primary interlocutors, and the organization of the source discourse. After a general introduction and some considerations of the pragmatic function of medical terms, three authentic cases are discussed. The article finishes with a discussion of the data and some conclusions.