Improvement in blood fluidity leads to the prevention of various lifestyle-related diseases. A raw material for improving blood fluidity has been long desired in the research area of functional and supplemental foods. We successfully showed an improvement in blood fluidity by the Zingiberaceae plant, Kaempferia parviflora. The rhizome of the plant reduced the blood passage time through a micro slit using a disseminated intravascular coagulation model. The mechanism was attributed to the activation of fibrinolysis, as demonstrated by elongation of the euglobulin lysis time and an in-vitro fibrinolysis assay. The active principles were determined to be methoxyflavones. The results show that the rhizome of K. parviflora is a promising candidate preventive agent for treating lifestyle-related diseases.