ABSTRACT
Traditional medicines, according to the World Health Organization, are defined as "the sum total of the knowledge, skill, and practices based on the beliefs, theories, and experiences indigenous to different cultures that are based and developed historically. Due to the increasing uses of traditional medicines worldwide, it seems that cognition of their principles and foundations are necessary." The two important schools of Traditional Persian Medicine [TPM] and Traditional Chinese Medicine [TCM] have many similar concepts; one of the most fundamental is the theory of Arkan in TPM and theory of five elements in TCM. This is a review study, which extracted, classified and compared related concepts in TPM and TCM, conducted on original sources. To use the experience of other researchers and to find published articles in this regard, the Web databases SID, Magiran, Iranmedex, Google scholar, Pubmed and Embase were searched. The results are categorized under 12 categories. Generally, although there are considerable similarities between theory and functions of Arkan in TPM and theory of five elements in TCM, there are differences between the basic principles and the outcomes of these two theories. The comparison between these two theories shows that although they derive from similar theoretical and philosophical origins, that TPM arises from a monotheistic [not necessarily Islamic] viewpoint while TCM comes mostly from a metaphysical point of view. Furthermore, there are four principles in TPM but five in TCM. In addition, principles in TCM and TPM differ as follows: while in the former, the principles [having interactions in a dynamic process] are assumed to be directly related to phenomena, in the latter, they are explained with the mediated concept of "Mizaj"