Objectives This study was aimed to propose the guideline of the diarrhea in Sasang Constitutional Medicine. Methods 1) Literature search It was investigated that the prescriptions stated the diarrhea as a main and accessory symptoms to be treated in "Donguisasangshinpyun", "Donguisusebowon Sasang Chobongwon", "Donguisusebowon Gabobon", "Donguisusebowon Sinchukbon", "Dongmuyugo" 2) Clinial paper search (1) The foreign papers were searched by using the search word with 'Sasang AND Diarrhea' in pubmed (http://www.ncbi.nlm.nih.gov/pubmed/) and The Cochrane Library(http://www.thecochranelibrary.com) (2) The domestic papers were searched by using the search word with 'Soeumin AND Diarrhea', 'Soyangin AND Diarrhea', 'Taeeumin AND Diarrhea', 'Taeyangin AND Diarrhea', 'Sasang AND Diarrhea' in NDSL (http://www.ndsl.kr), KISS(http://kiss.kstudy.com), Oasis(http://oasis.kiom.re.kr), RISS(http://www.riss.kr) (3) The extracted factors were the evaluations on the mainly complained symptom, adopted four constitutional therapy and efficacy. Results & Conclusions The guidelines for treating the diarrhea in the Four Constitutional Medicine are as follows. 1) It is to categorize the constitution. 2) The diarrhea of taeeumin is prescribed with 'A Series of Taeeumjowi-tang, Galgeunhaegi-tang, Cheongsimyeonja-tang, Sahyang-san, etc'. by classifying into cold, fever, consumption and addiction. 3) The diarrhea of soyangin is regarded as an internal disease and it is prescribed with 'Baekhaobuja-tang, Baekhaobujaijung-tang, etc'. by classifying taeeum symptom and so-yin symptom. 4) The diarrhea of soeumin is Mangeum-disease and 'Jeoryeongchajeonja-tang, Hyeongbangsabaek-san, Hwalseokgosam-tang, Hyeongbanggihwang-tang, etc'. is prescribed depending on the complication.