Based on theories from the

The Inner Canon of Yellow Emperor

（《黄帝内经》）， this paper explores the connotation of the principle "salty flavor can drain the kidney" and its application in the treatment of kidney diseases. By tracing the origins and conceptual evolution of "the kidney desires firmness" and "salty flavor can drain the kidney"， it is proposed that the notion of "the kidney desires firmness" not only reflects the kidney's normal physiological tendency toward storage and consolidation， but also implies a pathological tendency toward imbalance when excessive closure and storage occur. Furthermore， the connotation of "salty flavor can drain the kidney" is elaborated across three dimensions， including softening hardness and dissipating masses， entering the blood level to unblock the collaterals， and subduing hyperactive

yang

and calming rebellious

qi

. The core therapeutic objective is to restore the pathological state of excessive kidney closure. The clinical application of this principle in the treatment of kidney diseases is also discussed.