The production of Tiangui mainly depends on the filling of essence in the kidneys.

1. Substances necessary to promote human growth, development and reproductive functions and maintain women's menstruation and pregnancy. It comes from the kidney essence of men and women, and is gradually enriched by the nourishment of acquired water and grain essence.

"Su Wen. Ancient Innocence Theory": "When a woman is in the 27th year of the lunar month and the Tiangui arrives, the Ren pulse is strong and the Taichong pulse is strong. The menstruation is at the current time, so she has a son. The Ren pulse is weak in the 77th month and the Taichong pulse is strong. The pulse is weak and weak, the Tiangui is exhausted, and the tunnel is blocked, so the shape is bad and there is no child. ”

2. Another name for essence. From "Huangdi Neijing Taisu": Tiangui is the essence.

3. Another name for Yuanyin and Yuanqi. "Lei Jing. Zang Xiang Lei": Therefore, Tiangui, in the human body, is Yuan Yin, also called Yuan Qi.

4. Synonymous with menstruation. For example, "The Complete Prescriptions for Women" states that Tiangui expires, which refers to the late period of menstruation. Now rarely used.

"Tian" means that it comes from the innate world, and "Gui" means that its essence belongs to Gui water in the heavenly stems, which means yin in yang. Zhang Jingyue said: Fugui is the water of the sky, which is also the name of Qian. Therefore, Tiangui refers to the Yin Qi of Tianyi.

The gas turns into water, so it is called Tiangui. When it is in the human body, it is called Yuanyin, also called Yuanqi. Therefore, Tiangui is the innate essence, which has the function of transforming essence and blood, thereby enabling men and women to have reproductive capabilities.