TCM is one of the oldest and most widely-used indigenous medical systems in the world. It is difficult to effectively practice or evaluate TCM outside of its core framework, which includes a diagnostic system that is more conceptual and less technologically driven than that of conventional medicine. TCM diagnosis relies entirely on clinical symptoms and signs that are discerned by the practitioner. The establishment of diagnostic and prescriptive consistency is crucial for efficacy studies involving individualized treatments within the TCM framework. This study will examine the consistency of TCM diagnoses and herbal prescriptions under controlled conditions.