The main diseases and mechanisms of cyan, red, yellow, white and black are briefly described.

Cyan: the main cold syndrome,' pain syndrome, blood stasis, convulsion. Cold coagulation leads to qi stagnation and blood stasis, and the meridians are restrained, so the face is blue or even blue; Blood stasis in channels and collaterals, which is painful if it is blocked; Blood does not nourish tendons, and liver wind moves inward, leading to convulsions.

Color red: the main heat syndrome, red is true heat, slightly red is deficiency heat. Fierce and fierce, inspiring qi and blood, filling the pulse, proud of blood color, so the face is reddish.

Yellow: deficiency syndrome and dampness syndrome. Yellow is the image of spleen deficiency and dampness accumulation. When the spleen loses health, the water does not turn wet, and the qi and blood are not full, the complexion will turn yellow.

White: deficiency syndrome, cold syndrome, blood loss and qi deficiency. White is a symptom of poor qi and blood. Deficiency of yang, poor circulation of qi and blood, gas consumption and blood loss, deficiency of qi and blood, cold coagulation and contraction of meridians will all lead to pale complexion.

Black: kidney deficiency, blood stasis caused by drinking water. Black is the color of cold and water. Due to deficiency of kidney-yang, insolubility of water and drink, excessive yin and cold, blood loss of warm nourishment, meridian strain, qi and blood obstruction, and dystrophy of meridian skin, the complexion is gloomy.