The meaning of Qi as the commander of blood contains the following three aspects:

• Making Blood
  Qi is the motive power for making blood. Qi is indispensable when water and food are changed into food essence; food essence is then changed into nourishing Qi and body fluid; nourishing Qi and body fluid are turned into red blood ; the essence of life is changed into blood, and marrow transforms into blood.
  
  The functions of Qi mentioned above, however, are performed mainly by the functional activities of the relevant viscera and bowels. When Qi is sufficient, the functional activities of the viscera and bowels are full of vigour, and the ability to make blood is also strong. When Qi is insufficient, the functional activities of the viscera and bowels are weak, and the ability to make blood is also weak. Therefore, a deficiency of Qi often leads to a more deficiency of blood. The deficiency of both Qi and blood gives rise to such symptoms and signs as shortness of breath, lassitude, pale complexion, dizziness, dim eyesight, palpitation and others. In treating a deficiency of blood, TCM often adds drugs having the function of invigorating Qi to those having the function of enriching blond.
  
  For example, Chinese Angelica Decoction for Replenishing Blood is one of the prescriptions which functions well in enriching blood. It consists Fists of 6 grams of Chinese angelica root ;Radix Angelicae Sinesis) which has the property of enriching blood, and 30 grams of milkvetch root (Radix Astragali Seu Hedysari) whick has the function to invigorate Qi. Why? Because Qi, has the function of promoting the development of blood .

• Qi as the Driving Force of Blood
  Qi is also the motivating power which propels blood forward. On the one hand, it can propel blood forward directly, which is, what is called, "Qi in motion renders blood circulating normally. On the other hand, it can drive blood forward. indirectly by means of the functions of the relevant viscera and bowels, such as driving function of the Qi of the heart, dispersing function of the Qi of the lung, and smoothing and regulating functions of the Qi of the liver. Therefore, the stagnation or deficiency of Qi or the disorder of the relevant viscera and bowels, can block the flow of blood, and even cause blood stasis. So when treating the syndromes that are due to blood stasis, TCM not only prescribes drugs having the property of promoting blood circulation and resolving blood stasis, but also adds drugs having the property of promoting the circulation of, or supplementing Qi according to different causes. Meanwhile, it pays attention to recuperating the functions of the relevant viscera and bowels.
  
  
• Keeping Blood Flowing within the Vessels
  Qi (Vital energy) has the function of keeping blood circulating normally within, not extravasating, the vessels. This function of Qi is mainly based on the function of the spleen. For example, when Qi is insufficient, especially when the spleen fails to keep blood flowing within the vessels, various kinds of hemorrhage often occur. When treating them, TCM is not for using excessive homeostatic but mainly for using drugs having the function of invigorating the spleen to benefit Qi such as ginseng root (Radix Ginseng), milkvetch root (Radix Astragali seu Hedysari), large headed atractylodes rhizome (Rhizoma Atractylodis Macrocephalae) and licorice root (Radix Glycyrrhizae). In so doing, the homeostatic aim may be attained by recuperating the spleen's function of keeping blood flowing within the vessels.

The concept of blood as "the mother" of Qi has taco aspects. One is that Qi is in blood and carried by blood. The other is that blood permanently provides nutrients for the movement of Qi Therefore, Qi can not exist without blood. That is why those whose blood is deficient have deficient Qi. Those who have lost a lot of blood have less Qi. Because of this, in the treatment, Qi should be reinforced at the same time as blood is toned up, and vice versa.

Qi is also the motivating power in the development of body fluid. Body fluid is developed mainly through the functions of the spleen and stomach. It, however, has the ability to promote the functions of the spleen and stomach. So, when Qi is sufficient, the functions of the spleen and stomach are sound, and the body fluid is abundant. When Qi is deficient, the functions of the spleen and stomach are weakened, and the body fluid is insufficient.

The ascending, descending, exiting and entering of Qi is the motivating power for body fluid to be transported, distributed and excreted. There is a saying: "Qi has the function of promoting the circulation of body fluid and the excretion of water." Of course, Qi performs this function with the help of the lung, spleen, kidney, triple warmer, urinary bladder and relevant viscera or bowels.

Therefore, a deficiency or stagnation of Qi or abnormal function of the relevant viscera or bowels caused by any factor may lead to a disturbance in transporting, distributing and excreting body fluid, which is known as "Qi false to promote the circulation of body fluid" and "Qi is unable to help excrete water." Promoting the circulation of or supplementing Qi and promoting diuresis are good measures to be taken in solving this problem. meanwhile, the functions of the relevant viscera or bowels should be restored.

The guiding action of Qi can regulate and control the excretion of body fluid. The balance of the metabolism of fluid in the body can be kept only by this action of Qi. If Qi fails to control the excretion of body fluid, the body fluid will flow away without reason. For example, if defendingQi can not function well in regulating body fluid, spontaneous sweating will occur; if the kidney's Qi is insufficient in controlling body fluid, there will occur enuresis and polyuria. In our clinical treatment of these disorders, the method of invigoration Qi to control body fluid is often used.

Body fluid is also the carrier of Qi. Qi exists through its attachment to body fluid. Therefore, the loss of body fluid often damages Qi. For example, over-sweating or profuse sweating may damage Qi. Repeated severe vomiting and diarrhea cause heavy loss of body fluid, which, in turn, give rise to heavy loss of Qi.