This couplet is engraved on the side of the stone tablet of Tao Te Ching at the gate of Laozi Temple, an ancient building. In the upper right corner of the first couplet, it is marked "Masterpiece". Seven of the words are included in Kangxi Dictionary, but the rest can't be found in dictionaries. However, according to Taoist auspicious symbols, the first part reads "Jade Furnace Burning Life-prolonging Medicine" and the second part reads "The Right Way of Xiushou Pill". These fourteen words are all created according to the Taoist classics and the knowledge in the Six Classics, and they all have specific meanings! It's a Taoist couplet for health preservation and self-cultivation. These characters are constructed according to the method of keeping in good health and the connotation of Taoist cultivation, while the Taoist cultivation thought comes from Laozi and Zhuangzi, and the rest comes from the ideological cognition of Chinese medicine, which complement each other.

Home water, as its name implies, is its own water, that is, all body fluids and their transportation and distribution, including saliva and urine, which you mentioned naturally, and can also be interpreted as kidney of traditional Chinese medicine. Kidney is not only a visible liquid substance, but also refers to essence. Traditional Chinese medicine believes that the kidney is water dirty, and the five elements belong to water. Therefore, the water in the home should be understood as the kidney of traditional Chinese medicine. Here, the kidney is not only an organ but also a system.

Essence means subtlety, which is considered as the basic substance to constitute human body, maintain human growth and development and various functional activities in traditional Chinese medicine. It is divided into innate essence and acquired essence, which are interdependent and mutually utilized. Their functional sources are different, but they all belong to the kidney. Congenital essence is inherited by parents, that is, reproductive essence. It is this primitive substance that constitutes the development from embryo to life. After birth, people hide in their kidneys. The essence of the day after tomorrow comes from the spleen and stomach. It comes from Shui Gu's subtlety and the essence of zang-fu organs obtained from the digestion and absorption of food. It originates from the transportation of the five zang-fu organs to Shui Gu, and plays a role in nourishing and maintaining the organs. Su Wen's "Qian An's Innocence" said: "The kidney governs water and hides in the essence of the five internal organs." Kidney stores essence, which controls growth, development and reproduction, so it is closely related to health preservation. Therefore, Taoist practice or practice handed down from China tradition is all about abstinence, no desire to build a foundation and refine essence.

Kidney stores essence, and life cannot be separated from essence. Therefore, the kidney governing the yin and yang of the whole body is the foundation of the internal organs, and it is the house of fire and water, containing true yin and true yang. Kidney essence and kidney qi constitute the essence of kidney, which is divided into kidney yin and kidney yang. It is true yin and true yang, also known as Yuan Yin Yuanyang. True water is true fire, and the fire of life gate is the foundation of yin and yang of human body.

Kidney also controls water gasification, which mainly refers to the gasification function of essence in kidney. It plays an extremely important role in regulating the transportation and excretion of body fluids and maintaining the metabolic balance of liquid intake in the body. It can be divided into 1, which promotes visceral functions such as ascending and descending turbidity, 2, opening and closing bladder meridian, 3 and 3 jiao. In addition, the kidneys are salivating, which is what we call saliva. Therefore, both urine and saliva are contained in domestic water.

In addition, on the basis of the above, the kidney also has the function of controlling the intake of qi, that is to say, the kidney has the physiological functions of absorbing the clear qi inhaled by the lungs and preventing shallow breathing, that is, maintaining the circulation of qi and blood, and the normal circulation of qi and blood is the premise of health preservation. Therefore, this kind of "home water" is naturally a good medicine for health and longevity.