From a general point of view, the aim of this thesis is to study the appearance and the translation of the metaphor in a context that involves specialized texts. Our purpose is also to examine the historical expression of metaphor within aspects connected to its importance for creation of scientific terms. More precisely, the main object is to explore how metaphors have been used in the field of medical terminology and by which methods they have been translated across the languages. Our approach is based on the definition of conceptual metaphor conceived by Lakoff & Johnson as a product of projections made by the thought (mapping). According to that idea, the metaphor constitutes a universal and essential element of human language and, therefore, also a keystone of the human communication reproduced at every level of social activity. From the cognitive point of view, our approach is also based on the theory of blending proposed by Fauconnier & Turner. It is diachronic and multidisciplinary as well, which means that a particular focus has been placed on the etymology of medical terms, which we have explored in the scientific context where those terms have been created and used. The database in this study is composed of medical terms emerging from scientific texts that we have translated from French to Swedish.  During our analysis, we have explored the occurrence of conceptual metaphor across the source language and the target language (the last one is in fact represented in this thesis by four languages: French, Swedish, English and Polish). The translation methods have been analyzed according to the model of Vinay & Darbelnet.   Our result indicates that conceptual metaphor plays a crucial role in the creation of medical terminology. It indicates also that the conceptualization of a medical phenomenon (expressed by mapping and blending) is almost always preserved in its original form in the target language. This observation implies that cognitive factors are activated during the process of translation. Our conclusion is made within the historical and scientific context, in other words regarding the context where the metaphorical terms have been created and afterwards transferred to other languages.   Key words: conceptual metaphor, metaphorical term, cognitive, etymology, medicine, scientific language, mapping, blending, conceptual shift, linguistic shift, translation, source language, target language.