Objectives: Chunghyul-dan is a combinatorial herbal medicine, and previous studies reported it had therapeutic effects for microangiopathy, which is a major part. in the progression of stroke, as well as having anti-hypertensive, anti-hyperlipidemic, anti-apoptotic, anti-oxidative, and anti-inflammatory activities, Therefore, we examined the inhibitory effect of Chunghyul-dan on stroke occurrence in patients with silent brain infarction. Methods: We prescribed Chunghyul-dan at 600 mg a day to patients with silent brain infarction confirmed by brain MRI, and monitored stroke occurrence, drug compliances, and adverse effects for 1 year, We then performed follow-up brain MRI to detect new vascular lesions after 1 year of Chunghyul-dan medication. As for the subjects lost to follow-up, we assessed their prognosis after 1 year by telephone. Results: There were twenty-one subjects who were treated with Chunghyul-dan for more than 1 year, None of them experienced new clinical syndromes characterized by rapidly developing clinical symptoms and signs of focal and at times global loss of brain function, which could be accompanied with evidence of stroke occurrence, or any adverse effects during the Chunghyul-dan medication period. These results might be explained by various biochemical effects of Chunghyul-dan on microangiopathy, which is closely related with cell cycle progression, hypertension, hyperlipidemia, vascular inflammation, and oxidative damage. Of the 10 subjects lost to follow-up, six were reached; two of them had stroke occurrence. Conclusions: We suggest Chunghyul-dan could be useful for prevention of stroke occurrence in patients with silent brain infarction by preventing the progression of microangiopathy. Further study with a randomized controlled trial is needed to confirm this suggestion.