It is quite difficult for a neophyte to understand the difference between the functional and organ disease. Yet it is primordial. One speaks of an organ disease when an organ of the body is anatomically affected: a fracture, a ulcer, a tumour, a compression of an artery nerve, etc... It is a pathology which we can detect during the clinical examination or by the help of complementary examinations like radiography, echography, scan, MRI, etc.. One can localise and therefore treat the lesion. On the other hand we speak of a functional disease in case when no visible lesion is present but the organ does not function correctly. This situation is the case in 80% of consultations.