[Modern interpretation of "exterior-interior correlation between lung and large intestine" theory in acute and critical cases].

The "exterior-interior relationship between lung and large intestine" is one of the theories of traditional Chinese medicine, which is scientific in modern medicine. The ancients discovered the specific connection between the lung and large intestine, and constructed the theory of "exterior-interior relationship between lung and large intestine" through the Yin-Yang theory and the meridian attachment. The theory of "exterior-interior relationship between lung and large intestine" has been of great significance in the critical care field since the first study on intestinal tract and acute respiratory distress syndrome (ARDS) was carried out in the emergency medicine in 1980s. This article analyzes the consistence of lung and large intestine in early embryonic development, explains the close connection between the lung and large intestine through the intestinal flora translocation theory in sepsis, and reviews the immunoregulation mechanism of helper T cell 17 (Th17) in intestine and lung, and the possible molecular mechanism of immune response, so as to provide physicians with further exploration of the traditional theory of "exterior-interior relationship between lung and the large intestine".