Turkey has been witnessing purification activities in the field of medical terminology for a long period of time. However, the purified terms have not replaced the original ones possibly because of the lack of interest on the part of those who are engaged with purism. This is why Turkish cannot be used by the Turkish people as a language of science. Since there is a strong relationship between language and thought, an individual can think and act creatively through his/her mother tongue. Therefore, the present study concentrates on the concept of language, the close link between language and thought, the concept of native language, and the concept of terminology. In so doing, this study aims to argue for the significance of using mother tongue as the language of science. Within this scope, the study further focuses on some examples of purification such as the purification of the medical terminology.