According to the theory of traditional Chinese medicine, the heart is the master of blood vessels, and its color is reflected in the face, that is, the color of the heart is reflected in the face. If the face is rosy, it means that the heart energy is sufficient and the blood flow is smooth. If the face is grayish, it means that the heart qi is insufficient or the heart qi is stagnant resulting in poor blood flow, so patients with deficient heart yang or stagnant blood vessels can have a grayish complexion. Also, it is related to the spleen and stomach, which is the source of Qi and blood biochemistry. Only when Qi and blood are sufficient can blood have a normal material base supply. If the spleen is deficient and the qi and blood are deficient, the facial blood vessels will not be moistened and will also become gray.