Congenital essence is the base of constitution and decides the state of constitution. If constitution is different, its susceptibility to invasion of pathogenic factors is also different. Many hereditary or familial diseases all are related to the constitution of parents and their illness. Besides, the maternal nursing and care during pregnancy exerts great effect on the constitution of fetus.

After birth, the base of constitution is fixed and usually unchangeable. In this sense, the congenital base of constitution influences the whole life of a person. However, the living state after birth also influences constitution. TCM holds that the cultivation of health after birth can accumulate essence to improve constitution, making strong constitution stronger and weak constitution better. On the contrary, lack of proper cultivation of health after birth may make strong constitution weaker and weak constitution worse or fatal. Of course the change of constitution is a slow process.