Objective: To investigate the influence of Fuzhi Capsule on rat with vascular dementia and on expression of inducible nitric oxide synthase(iNOS) in brain hippocampus

and to explore the related mechanisms. Method: Sixty SPF rats were randomly divided into 4 groups(n=15 each)

the vascular dementia of rat was reproduced by bilateral carotid artery ligation. Afterwards

the animals were received different treatments: Fuzhi capsule group(3.0 g ·kg-1 ig daily)

aricept group(0.05 mg ·g-1 ig daily)

sham operation group and model group(saline 10 mL ·kg-1 ig daily). After 4 weeks of treatments

the behavioral experiments and expression of iNOS in hippocampus were determined. Result: The experiment showed that the learning achievement(finding the platform within 2 min) and memory performance(across the platform within 2 min in the other three quadrants) in the model group were decreased. On the other hand

the learning achievement and memory performance were improved in the treatment groups(P<0.05 or P<0.01). Pathological morphology suggested that the hippocampus iNOS expression was significantly increased the model group compared with sham operation group

and Fuzhi Capsule and aricept could make the expression of iNOS down. The effect of Fuzhi Capsule was more apparent compared with aricept. Conclusion: Fuzhi Capsule has a significant protective effect on vascular dementia

and the mechanism might be related with inhibiting iNOS expression.