In the Zang-fu concept
As a "Zang" of the Zang-fu viscera, spleen is one of the Yin organs. It is the origin of blood, rules transformation and transportation. The spleen extracts essences from food and which later becomes Qi and blood . It directs the ascending movement, prevents extravasations of blood, and dominates muscles. The spleen assists with water metabolism, opens into the mouth and is manifest on the lips. It also houses the Yi . The peak energy time for the Spleen is 9-11am. The fluid secretion is saliva.