In TCM, disease is generally 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. Therapy is based on which "pattern of disharmony" can be identified. In the case of the meridians, typical disease patterns are invasions with wind, cold and damp Excesses.
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.
TCM and its concept of disease do not strongly differentiate between cause and effect. In theory, however, endogenous, exogenous and miscellaneous causes of disease are recognized.
