Conceptions about functions of large & small intestine[LI & SI] were focused on the vermiculation in "Somun(素問) Yeongranbijeonron(靈蘭秘典論)". However, functions of large & small intestine includes more. In Oriental Medicine, there are sentences in "Hwangjenaegyeong(黃帝內經)" "LI manages Fluid [津] and SI manages Humor[液]" It means that LI & SI have an each role in digestion besides vermiculation. In that reason, we try to find out the meaning of the functions of LI and SI in digestion through bibliographic review. As a result, LI and SI have a digestic function by Separating the Clear which includes Fluids and Humor and the Turbid which is relatively useless to the Clear.