Concept of disease

In general, disease is perceived as a disharmony (or imbalance) in the functions or interactions of yin, yang, qi, xuĕ, zàng-fǔ, meridians etc. and/or of the interaction between the human body and the environment.[72] Therapy is based on which "pattern of disharmony" can be identified.[73][74] Thus, "pattern discrimination" is the most important step in TCM diagnosis.[73][74] It is also known to be the most difficult aspect of practicing TCM.[75]

In order to determine which pattern is at hand, practitioners will examine things like the color and shape of the tongue, the relative strength of pulse-points, the smell of the breath, the quality of breathing or the sound of the voice.[76][77] For example, depending on tongue and pulse conditions, a TCM practitioner might diagnose bleeding from the mouth and nose as: "Liver fire rushes upwards and scorches the Lung, injuring the blood vessels and giving rise to reckless pouring of blood from the mouth and nose.".[78] He might then go on to prescribe treatments designed to clear heat or supplement the Lung.