This study was performed to evaluate the effects of Koamsimsinwhan (without Cinnabarite) on depression in CMS-treated rats. Rats of trial groups were exposured to chronic mild unpredictable stress for 4 weeks. These CMS-treated rats were stratified into Koamsimsinwhan(without Cinnabarite) group and vehicle(non-drug) group. And there were control rats excluding both CMS and Koamsimsinwhan(without Cinnabarite). Forced swimming test, general activity test and immunohistochemical test(measuring the level of manifestation of c-Fos in PVN) were executed to evaluate the effects of Koamsimsinwhan(without Cinnabarite) on depression after 4 weeks of CMS treatment. The results were as follows 1. In FST, depression was induced from CMS treatment and was supressed with Koamsimsinwhan(without Cinnabarite). 2. The increased activity of nerve cell in PVN, which refers to stress, was induced from CMS treatment and normalized with Koamsimsinwhan (without Cinnabarite).