The theories such as meridian tropism, four natures and five flavors, lifting, lowering, floating and sinking all explain the properties of Chinese medicinal herbs from various points of view, which jointly constitute their proper-ties and actions. Whereas pathological changes in the same viscus or meridian are different in cold, heat, asthenia or sthenia, and in adverse ascending or descending, and the medicinal herbs which are attributed to the same meridian also have the difference in cold, warm or cool, tonifying or reducing and adverse descending or ascending.
For example, Mahuang (Herba Ephedrae), Huangqin ( Radix Scutellariae ) and Shashen ( Radix Adenophorae Strictae) are all attributed to lung-meridian and can all treat cough, but Mahuang (Herba Ephedrae ) pungent and slightly bitter in flavor and warm in nature tends to lifting and floating in actions, so it can disperse the lung to relieve cough and asthma and is indicated for cough and asthma due to exogenous wind and cold; Huangqin (Radix Scutellariae) bitter in flavor and cold in nature tends to sinking and lowering in actions, so it can clear away heat, and purge excessive fire and relieve cough and asthma due to lung-heat; Shashen (Radix Adenophorae Strictae) sweet in flavor and cold in nature tends to sinking and lowering in the action, therefore, it can nourish yin to promote secretion of the body fluids and is indicated for cough due to insufficiency of lung-yin. Therefore when you apply medicinal herbs in clinic, you must combine their various properties and effects to give them an all-round consideration so that you can select and apply them correctly and avoid one-sidedness.
But in clinical practice, owing to frequent occurrence of transmission of a disease between zangfu-organs or meridians in addition to the Chinese medicinal herbs only for one viscus or meridian, those for the other viscera or meridians are also usually used together. For instance, when treating lung disorders affects the spleen, both the medicinal herbs for treating lung disorders and invigorating the spleen should be used, which is called supplementing the spleen to nourish the lung. For the same reason, a syndrome with hyperactivity of liver-yang due to insufficiency of kidney-yin should be treated in combination with the medicinal herbs nourishing kidney-yin to have the liver nourished and deficiency of yang calmed, which is the method of nourishing renal yin to tonify liver yin.
