Xu(deficiency)and Shi (Excess) of the Eight Principles

Xu(deficiency) and shi (excess) are two principles which are used to analyze the strength or weakness of body resistance and the pathogenic factors during the process of disease development.

Generally, syndromes of the xu type indicate diseases and symptoms caused by the weakness and insufficiency of body resistance.Sydromes of the shi type refer to diseases and symptoms indeuced by an overabundance of exogenous pathogenic factors.Xu syndromes are mainly due to an insufficiency of antipathogenic factors when exogenous pathogenic factors are also in a weakened state. Shi syndromes are mainly due to an excess of exogenous pathogenic factors, with body resistance not yet weakened. Mixture syndromes of xu and shi also occur.

Xu syndromes can be further classified into qi deficiency , blood deficiency, yang deficiency, and yin deficiency with varied clinical manifestations. Shi syndromes may be caused by qi stagnation, blood stasis,phlegm obstruction, stagnancy of water,and parasites with complex clinical manifestations. The general xu syndromes include lassitude, emaciation, sluggishness, pale complexion,palpitation,shortness of breath, spontaneous sweating, night sweating, insomnia, poor memory, loose stool,frequent urination or incontinence of urine,pale tongue proper without coating, thread and weak pulse, etc.

Shi syndromes generally include coarse breathing, irritability, sonorous voice,pain and distention in the chest and abdomen,pain and distention aggravated by pressure, constipation, dysuria, thick and sticky tongue coating, forceful pulse, etc.However, the patient's body can still remain strong and vigorous.