Fei and Pi
assist each other in Qi generation and water metabolism.
Fei inhales fresh air and distributes water to all parts of the body, while Pi
absorbs nutrients by transforming and transporting food and water. Pi supplies Fei with essential substances. “Pi
is the origin of acquired Essence, and Fei
is the axis of Qi.” Fei
distributes and regulates the water passage, assisting Pi
in its function of transporting body fluid. Deficient Pi
cannot transform phlegm and allows it to accumulate, or may stagnate fluid, leading to cough with excess sputum and dyspnea.