Constitution varies from person to person and the study of such a variation is helpful for expounding pathogenesis.

Constitution is generally classified into two categories: strong constitution and weak constitution. For thoroughly explaining the pathogenesis of various diseases, there are different ways to divide constitution in TCM, generally including classification according to Fin and Fang theory, classification according to five elements theory, classification according to the viscera, classification according to qi, blood and body fluid, and synthetic classification. These ways to classify constitution are complicated, the following is a brief introduction to some commonly encountered types of constitution.

Superabundance of Fang produces heat. So this type of constitution is marked by reddish complexion, sonorous voice, warm hands and feet, dry stool, slightly yellowish urine, tolerance to cold and intolerance to heat as well as slightly rapid pulse. This kind of syndrome can be further divided into specific types according to location of heat in different viscera, such as up-flaming of heart-fire, hyper-activity of liver-Fang and exuberant fire in the heart and the liver, etc.

Superabundant Fin produces cold. So this type of constitution is marked by bluish complexion, low voice, cold hands and feet, soft stool, clear urine, tolerance to heat and intolerance to cold as well as slightly slow pulse, etc. This kind of syndrome can be further divided into specific types according to location of cold in different viscera, such as retention of cold in the lung, stagnation of cold in the liver meridian and accumulation of cold in the spleen and stomach, etc.

Deficiency of yang generates cold. So this type of constitution is marked by whitish complexion, cold feet and hands, spontaneous sweating, impotence, diarrhea, profuse clear urine and deep-slow pulse. This kind of syndrome can be further divided into specific types according to location of cold in different viscera, such as insufficiency of heart-yang, insufficiency of spleen-yang, insufficiency of kidney-yang (decline of fire in life-gate), etc.

Deficiency of yin means insufficiency of yin-essence and deficiency of yin generates heat. So this type of constitution is marked by reddish cheeks, emaciation, feverish sensation in the soles and palms, dysphoria, insomnia, night sweating,  seminal emission,  dry stool,  scanty brownish urine and thin-rapid pulse, etc. This kind of syndrome can be further divided into specific types according to location of heat in different viscera, such as insufficiency of heart-yin, insufficiency of liver-yin, insufficiency of lung-yin, insufficiency of spleen-yin and insufficiency of kidney-yin, etc.

Deficiency of qi means insufficiency of the primordial qi and deficiency of qi leads to hypofunction of the viscera. So this type of constitution is marked by sallow complexion, dispiritedness, lassitude, low voice, poor appetite and weak pulse, etc. This kind of syndrome can be further divided into specific types according to the viscera involved, such as insufficiency of heart-qi, insufficiency of lung-qi, insufficiency of spleen-qi and insufficiency of kidney-qi, etc.

Blood deficiency leads to malnutrition of the viscera. SO this type of constitution is marked by pale complexion, dizziness, numbness of limbs, weakness of limbs, pale lips and nails, insomnia, dreaminess, scanty light-colored menses, light-colored tongue and thin-weak pulse, etc. This kind of syndrome can be further divided into specific types according to the viscera involved, such as insufficiency of heart-blood and insufficiency of liver-blood, etc.

Exuberant dampness is caused by metabolic disturbance of body fluid due to prolonged living in humid areas and inhibited transformation of qi. The usual symptoms are obesity, dizziness, chest oppression, profuse phlegm, frequent nausea, poor appetite, mucous stool, profuse menorrhea, thick-greasy tongue coating and taut-slippery pulse, etc. This kind syndrome can be further divided into specific types according to the viscera involved, such as accumulation of phlegm-dampness in the lung, phlegm-dampness encumbering the spleen, phlegm-turbidity disturbing the heart and phlegm blocking the meridians, etc.

Constitution with blood stasis means that internal retention of blood stasis due to unsmooth circulation of blood. The usual symptoms are grayish complexion, heaviness or pain of the head and limbs, or mass in the body, irregular menstruation or dysmenorrhea or purplish menses with blood clot, purplish tongue or tongue with petechia, thin and unsmooth pulse, etc. This kind of syndrome can be further divided into specific types according to the viscera involved, such as blockage of the liver collaterals, blockage of the heart meridian and blockage of the uterus, etc.

The types of constitution sometimes are mingled with each other, such as constitution with superabundant yin mingled with deficiency of yang, constitution with deficiency of yang mingled with deficiency of qi, constitution with exuberant dampness mingled with blood stasis, etc.