What is meant by medicine being prescribed by meridian?

 What is meant by medicine being prescribed by meridian?

A: Applying medicine according to the meridians is to demonstrate the position where the medicine will have the most effect on. Medicines are grouped according to their natures. Meridians mean the different internal organs that are linked by energy channels. 

There are some medicines that apply to only one meridian, but others can be applied to several meridians. The matching of medicines with meridians helps raise the efficacy of the medicine. However, since the meridians and the internal organs are interrelated and influence one another biologically, in applying medicines it is necessary to consider the relationship between the meridians and the internal organs. Therefore, most TCM practitioners usually apply medicines that match more than one meridian.