One of the basic theories in traditional Chinese medicine, according to which the physical structure and physiological phenomena of the human body as well as the pathological changes are in adaptive conformity with the variations of the natural environment, and hence in diagnosis and treatment the influences of environmental factors such as climatic conditions, geographical localities, should be considered.

As follows, here are some commonly used citations£º

Human, Heaven and Earth are a trinity.

Human depends on the qi of Heaven and Earth to exist, and delevops along with the law of the four seasons.

The five zang-organs correspond to the four seasons.

One must know in advance the condition of the year's qi to avoid attack on the harmony of man and nature.