Objectives : During several thousand years, Peucedanum Japonicum Thunberg has been considered as a vegetable side dish in Korea. There is folk knowledge that Peucedanum Japonicum Thunberg prevents vascular disease such as stroke. To identify the effects Peucedanum Japonicum Thunberg, we made up its extract and named it as KH020. Then, we employed common carotid artery ligation (CCAl) surgery for vascular dementia model (VDM), and two types doses of per os (per oral: p.o) treatment. Methods : To confirm prevention and recovery effects for vascular dementia, we treated two doses (100, 400 mg/kg) KH020 in male C57BL/6 mouse during 7 days. After treatment, animals were CCAl operated, and given time to recover. Then, animal were tested in a Y-maze and passive avoidance test. Results : Y-maze results demonstrated that cognition and memory performance were decreased in the VDM group, compared to the sham group. KH020 treatment abolished these effects significantly. The results from the passive avoidance test showed the same phenomenon, but it was not statically significant. Conclusions : Therefore, KH020 prevents the onset of vascular dementia. In fu ture studies, we will evaluate KH020 in regard to alzheimer dementia.