Tianmabianchunzhigan

The study will be a 36-week multicentre, double-blind, placebo-controlled phase Ⅱb trial in China. Total 360 participants aged 55-80 years will be randomized to Tian Ma Bian Chun Zhi Gan group (84mg per day) or to placebo group. The primary endpoint will be Vascular Dementia Assessment Scale-cognitive subscale and Clinical Dementia Rating-Sum of Boxes. Secondary outcomes included changes in Mini-Mental State Examination, Clock Drawing Test, Delayed Story Recall and Ability of Daily Living. Patients' safety will be assessed by recording of adverse events, clinical examinations, electrocardiography and laboratory tests. The patients, caregivers, and investigators will be blinded to the treatment allocations.