Jin Ye (or Jin Je) are the body fluids that flow within us and are important for the correct functioning of our organs, muscles and joints. Some examples of these fluids are sweat, mucus, saliva and semen but any fluids excreted by the body can fall within this category.
Jin fluids are those that are pure and thin and are used to nourish the muscles and skin. They circulate primarily close to the exterior of the body and are under the control of the Lung which disseminate them. The Upper Burner (including the Lung) is responsible for transforming them. They are relatively fast moving compared to Ye fluids.

Ye fluids are denser and move slower within the core of the body. They are transformed by the Spleen and Kidneys and are excreted by the Middle and Lower Burners. Ye fluids nourish the bones, organs and brain.
Both Jin and Je fluids are closely related to blood and feed, move and derive from the same sources. Losing Jin or Ye fluids can result in a deficiency of Qi within the body. Conversely, a lack of Qi within the body can result in stagnant or deficient Jin Je, the body not having enough Qi to move the fluids.
Fluid deficiency within the body can be recognised by dryness in the body, thirst and dry excretions. The tongue will be red with little to no coating and the pulse thin and rapid.
Fluid retention within the body can be recognised by bloating, poor appetite and sluggishness. The tongue will be wet with white coating and the pulse will be slippery and wiry.
Jin Je are derived mainly from the foods we eat. After processing (in the Stomach), the pure is separated from the impure, with the turbid fluids excreted by the body. The Spleen, Kidneys and Lungs are all intimately involved in transforming the raw energy (foods) into the Jin Je.