Organ and meridian diagnostics is a classic TCM diagnosis which includes tongue and pulse diagnosis. It is required for a successful therapy and for setting up a prevention plan. Organ and meridian diagnostics is based on two fundamental principles: First of all, it is based on a correlation between external symptoms and the internal organ systems. Secondly, the holistic analysis which reflects the TCM philosophy, a part of the body never isolated itself from the body as a whole. At the end, a diagnosis and differential diagnosis of the disease patterns are provided of functional organ systems with their corresponding meridians. This is all done according to the concepts and theories of traditional Chinese medicine.