For instance, Mahuang (Herba Ephedrae) and Xingren ( Semen Armeniacae Amarum ) effective to syndromes of the disorder of the lung meridian marked by cough and dyspnea are attributed to the lung-meridian; Qmgpi ( Pericarpium Cirri Reticulatae Viride ) and Xiangfu (Rhizoma Cyperi) indicated for syndromes of the disorder of the liver-meridian marked by distending pain of breast and hypochondrium and hernia pain are attributed to the liver-meridian. So generally speaking, what meridian or meridians a medicinal herb is attributed to is just related to the certain meridian or meridians on which the herb may work.

If certain medicinal herb can work on several meridians, which means the medicinal herb can be used widely to treat the disorders of these meridians. From the above, we can see that meridian tropism of Chinese medicinal herbs is summerized from the therapeutic effects through a long time of clinical observation, and being practiced repeatedly, gradually develops into a theory.

The theory of meridian tropism plays a certain role in clinical selection of Chinese medicinal herbs according to syndromes, giving a rise of direction and strengthening the therapeutic effects. For instance, medicinal herbs cold in nature have effects of clearing away heat, which also have the differences in tendency towards clearing away heat in the heart, liver, lung, or stomach; those hot in nature can all warm the interior to expel cold, but their effects also have the differences in warming the spleen, stomach, lung or kidney. Therefore, when you prescribe medicinal herbs, you should select those that work on the diseased viscus or meridian or some viscera or meridians in the light of their properties of meridian tropism to achieve desired therapeutic effects. In addition, you can take meridian tropism of Chinese medicinal herbs as a clue to probe their potential effects of some medicinal herbs and to extend their applying range.