The Iranian traditional medicine was based upon a particular set of concepts and fundamental. These stable and fixed roots of dynamic medicine and the appropriate understanding of medicine have ended in useful results in diagnosis and treatment of diseases and more importantly in preservation of health and disease prevention. The theoretical aspect of Iranian medicine addresses the concepts and fundamentals of medicine, on which the development and balance of human being is dependent. The concepts include seven components of elements, temperaments, humors, organs, spirits, faculties, and activities. Appropriate understanding of these components is invaluable in development of drugs, treatment of diseases, nutrition, and preservation of health. Therefore, learning natural issues (omur-e Tabieia) was of great priority for physicians and pharmacists of Iranian medicine. Also, as was mentioned above, for appropriate understanding of these topics good understanding of philosophy is required.