According to the theory of zang-xiang in TCM, the zang-fu organs of human body can be divided into three categories: zang-fu, fu-fu and extraordinary fu-fu. The so-called "five internal organs" refer to the heart, liver, spleen, lung and kidney; "Six fu organs" are gallbladder, stomach, small intestine, large intestine, bladder and triple energizer; "Qi Heng Fu" refers to brain, marrow, bone, pulse, gallbladder and female fetus (uterus).

Stomach, belonging to fu organs, is also called epigastric pain. Its main physiological functions are as follows:

(1) Shui Gu: That is, the stomach can accept and contain food, and can preliminarily digest food to form chyme. Therefore, the stomach is also called "Taicang", "the sea of water valley" and "the sea of qi and blood in Shui Gu".

(2) Dominating purgation, reducing harmony: In the theory of Tibetan images, the physiological function of the whole digestive system is summarized by spleen ascending stomach descending. Therefore, the function of lowering blood pressure of the stomach includes not only pushing decomposed food into the small intestine for further digestion, but also the function of transporting food residues from the small intestine to the large intestine and transferring dregs from the large intestine.

The rise and fall of the stomach is the decline of turbidity, which is the premise of acceptance. Therefore, stomach disharmony will not only affect appetite, but also cause bad breath, abdominal distension and constipation due to turbid qi.