[Analysis on the defensive function of defensive qi in Huangdi Neijing (The Yellow Emperor's Inner Classic)].

The defensive function of defensive qi in Huangdi Neijing (The Yellow Emperor 's Inner Classic) includes the effect of immune system of human body against the pathogen invasion. According to the basic research, it is believed that the circulation of defensive qi in meridian is interpreted as the flow of interstitial fluid in the low hydraulic resistance channel that is overlapped with lymphatic vessels, transporting the antigen information from interstitium to lymph nodes and generating adaptive immune response. Enhancing meridian circulation and promoting the flow of interstitial fluid may improve the immunity, which demonstrating the thought of traditional Chinese meridian as pathogens failing to invade the body when the anti-pathogenic qi is strong enough inside.