The doctrine of the mean is the fundamental principle of health preservation. Qi and blood in the human body are also a pair of yin and yang, with blood as the body and qi as the yang. Blood is the mother of qi, and qi is handsome for blood. Qi deficiency can easily lead to congestion, such as tumors and thrombosis; If you are too angry, you will easily get diseases such as cerebral hemorrhage. Therefore, only the balance of qi and blood can make people healthy.