Kimi(氣味) means five tastes(五味), sour, bitterness, sweetness, hot taste and astringency, and four conditions(四氣), cold, hot, warm and cool, in the oriental medicine. This is defined based on yn-yang 5 evolutive phasis(陰陽五行), and 5 evolutive phasis on the change of season. Four seasons, spring, summer, autumm, winter are clearly different but, the rainy season(長夏) is not. In the thee of Ki (氣), not worm not hot(平) is included in addition to the four conditions that is because the rainy season is not differentiated clearly. KImi have realations to the four seasons, that is, warm and hot taste is considered as spring, hot and astringency as summer, not worm not hot and sweetness as rainy season, cool and sour as autumm, and cold and bitterness as winter. 4 conditions can be classified more detail, because the changes of the seasons are continuous. In the action mechanisms, Gardeniae Fructus reduces Heat of Insufficency Type(虛熱) of the upper class of medicinal herbs(上焦), and Rhel Rhizoma reduces Exessive Heat(實熱) of the under class of them(下焦). The assay methods for four groups medicines can be developed in three ways according to the indicators as follows. First, by the indicator which defines cold-acting medicine(寒性藥) such as Rhei Rhizoma, Coptidis Rhizoma, Scutellariae Radix, Gardeniae Fructus and is differentiated clearly from Hot-acting medicine(熱性藥) at the same time. Second, when the medicines are classified into another four groups as Drugs for Dispelling Internal Cold(溫裏藥), Drugs for Relieving Exterior Syndrome(解表藥), Drugs for Dispelling Phlegm(祛痰藥), Drugs for Regulatings Ki Flow(理氣藥), by the indicator which satisfies each group and is differentiated from other groups, at the same time. Third, by the indicator which has to be defined for each medicinal herb for four classification, individually.