Blood is a dense form of Qi, which flows all over the body. There is a saying that “where the mind goes, Qi flows and where Qi flows the Blood is sure to follow.” Blood’s primary function is to nourish the body and complement the nourishing action of Qi. The Blood relies on the generating, pushing and holding action of Qi, while Qi relies on the nutritive function of Blood. When lying down, the Blood regenerates itself in the Liver, it is important to have adequate rest (especially lying down), in cases of insufficient Blood.
Blood has a moistening function, which Qi does not have. The Blood ensures that body tissues do not dry out. It moistens the eyes and sinews, so that the eyes can see properly and the sinews are flexible and healthy. It also moistens the skin and the hair, ensuring that the skin is not too dry and that the hair remains shiny and healthy. Blood also provides the material foundation for the Mind; it houses and anchors the Mind, providing the harbor within which the Mind can flourish. The “Spiritual Axis” says: “When Blood is harmonized, the Mind has a residence”. If Blood is deficient, the Mind will be without foundation and become unhappy or uneasy. This may manifest as a vague anxiety, slight irritability, or a feeling of dissatisfaction. When asleep at night the Blood naturally embraces the Mind, but if Blood is deficient the Mind “floats” resulting in insomnia. The main sources of Blood are the Spleen and Stomach. Lung makes Blood move. In Chinese Medical thinking, Blood is generated by the interaction of the Stomach, Spleen and Kidney. To nourish Blood, tonify the Spleen and Kidneys. The Heart, Spleen and Liver are the most important organs in relation to Blood. The Heart governs Blood, the Spleen holds Blood in, and the Liver stores and cleans the Blood.
Blood and Essence mutually affect each other. Each can transform into the other. Essence plays an important role in the formation of Blood. On the other hand, Blood continually nourishes and replenishes the Essence.