Understanding the Five Fluids and Their Role in Health

The Yellow Emperor asked Qi Bo: “Water and food enter through the mouth and are transported to the stomach and intestines. The fluids derived from these foods are categorized into five types: In cold weather, or when one dresses too lightly, it transforms into urine and Qi; in hot weather, or when one dresses too warmly, it becomes sweat; when sadness or grief occurs, and the Qi is disturbed, it forms tears; when there is heat in the middle burner and the stomach functions sluggishly, it rises and becomes saliva; when the body is invaded by pathogenic Qi, causing Qi stagnation and obstruction, the water Qi accumulates, leading to water retention. While I understand these phenomena, I still do not fully grasp how the five fluids are generated. Please explain the underlying principles.”

Qi Bo replied: “Water and food enter through the mouth, and each has its own flavor, which is then directed to the corresponding organ. The fluids follow the pathways suited to each organ, with the San Jiao (三焦, sān jiāo) expelling the Qi to nourish the muscles and fill the skin. This is called Jin (津, jīn), and the fluids that do not move but remain stagnate are called Ye (液, yè).”

“In hot weather, when one wears clothing that is too thick, the pores open, and sweat is produced. If cold pathogens are trapped between the muscles, they condense the fluids into foam-like substances, which cause pain. In cold weather, when the pores close tightly, Qi and moisture cannot be expelled through the sweat pores. Instead, it flows downward to the bladder, resulting in urine and Qi.”

“Among the five internal organs and six fu organs, the heart is the ruler. The ears are responsible for hearing, the eyes for vision, the lungs act as the ‘prime minister’, the liver as the ‘general’, the spleen as the ‘guardian’, and the kidneys govern the bones and shape the body. Therefore, the fluids from the five organs and six fu organs flow upward to nourish the eyes. When the heart is disturbed by sadness or grief, it creates a Heart Vessel (心系, xīn xì), which causes an upward movement of the lungs, leading the fluids to overflow upward. This irregular movement causes coughing and tearing.”

“If there is heat in the middle burner, the stomach digests food too quickly, and parasites move up and down in the intestines. If the food and water in the stomach stretch the organs, the stomach becomes sluggish. This sluggishness causes Qi to reverse, leading to the formation of saliva.”

“The fluids from the five grains transform into fat and oils, which permeate the bones and enter the bone cavities. These fluids ascend to nourish the brain and descend to support the reproductive organs.”

“If Yin and Yang cannot harmonize, the fluids flow downward to the Yin orifices, leading to a reduction in marrow fluids. Excessive fluid leakage results in deficiency of true Yin, which causes lower back and leg pain, and weakness in the shins.”

“If the Qi pathways are blocked, the San Jiao (三焦, sān jiāo) cannot properly circulate, and the fluids fail to transform. The ingested food and water accumulate in the stomach and intestines, and eventually the waste exits through the large intestine. It remains trapped in the lower burner, unable to be processed into bladder fluid, leading to swelling in the lower abdomen and water retention, which manifests as Zhang Bing (胀病, zhàng bì).”

“The normal and abnormal situations of these five fluids and their movement depend on whether the Qi pathways are functioning properly.”