Night sweats are mostly attributed to

yin

deficiency， where

yin

fails to restrain

yang

， leading to internal generation of deficiency heat. At night， defensive

yang

enters the interior while the exterior is left unprotected. The internally generated deficiency heat disturbsfluids， causing their leakage and resulting in night sweats. However， clinical observation shows that not all cases can be explained by

yin

deficiency alone， and many doctors throughout history have proposed different perspectives. Based on the nocturnal characteristics of "

yang

entering

yin

" and "defensive

qi

circulating within

yin

"， as well as the sweating mechanism of "

yang

acting upon

yin

causes sweat"， this article reviews the pathogenesis of night sweats. Although

yin

deficiency is the main theoretical basis， the pathogenesis is complex and also includes

yang

deficiency with failure to secure， exuberant

yang

heat，

yin

excess restraining

yang

， internal blood stasis obstruction， and prolonged accumulation of dampness-heat. Ultimately， all pathogenesis is rooted in the imbalance of

yin

-

yang

and cold-heat， providing new ideas for syndrome differentiation and treatment of night sweats.