The kidneys are a vital excretory organ that creates urine to help the body gets rid of toxins and unwanted water in western physiology. TCM view the kidneys as a very important organ that not only regulates the urinary system but also exercises control over the reproductive, endocrine and nervous systems.
The kidneys are the organs responsible for human development, because they store Jing energy. Jing is an essential substance, closely associated with life. It is needed for reproduction, growth development and maturation. For example, conception is made possible by the power of Jing, growth to maturity is the blossoming of Jing, and aging reflects the weakening of Jing. As time passes, Jing decreases, causing both vitality and kidney Qi to decline. This decline is the normal aging process.
The kidneys play an important role in water movement and balance of the whole body. The kidneys govern water by regulating its distribution and excretion. This traditionally described as the vaporizing kidneys power. They can differentiate between clean water, which is recycled and used by the body, from turbid water that is turned into urine. The separation of these two is the vaporization process.