The Unani Medicine is based on certain fundamental theories and concepts, such as Mizäj (temperament), Akhlät (humours) and Quwä (Faculties) etc. Nuzj (concoction) is a concept of Unani Medicine, not simply a term. The process of Nuzj is related to mädda (matter) either normal or abnormal. Therefore, each type of mädda in the body passes through the process of Nuzj and thereafter the fate (assimilation or elimination) of mädda can occurs. Thus, the process of Nuzj plays an imperative role in the preservation and restoration of health. The material on this concept is scattered in classical Unani literature and not clarified. The present paper has attempted to focus the concept and to make it more elucidated.