Objectives : This study was carried out to investigate the effects of Coicis Semen Extract (CSE) on the experimental colitis induced by dextran sulfate sodium (DSS) in mice. Methods : Experimental colitis was induced by daily treatment with 5% DSS in the drinking water for 7 days in 6-week-old male ICR mice. The colitic mice were divided into three groups: the normal (N) group consisted of mice that were not inflammation-induced. The control (C) group was composed of untreated colitis elicited mice. The sample (S) group was administered CSE after colitis elicitation. The effects on colonic mucosal ulcers were evaluated by the morphological, histological and immunohistochemical change of the large intestine. Results : Inhibition of LPS-induced NO decreased in the S group. Inhibition of LPS-induced iNOS and COX-2 mRNA noticeably decreased in the S group from 0.25 mg/ml. In the common morphological and histochemical change, the erosion and the infiltration of inflammatory cells increased in the C group, while they noticeably decreased in the S group. The length of colon was shortened more in the C group than in the S group. The distributions of MUC2 and Hsp70 treated with CSE increased noticeably more in the S group than in the C group (p<0.05). It was confirmed histochemically and immunohistochemically that the distributions of iNOS, COX-2, MAC387, serotonin, apoptosis and PCNA treated with CSE decreased in the S group more than in the C group (p<0.05). Conclusions : It is confirmed that CSE has cytoprotective effect, so can alleviate inflammation process. Therefore, it is expected to have potential protective effect on colitis.