Herbs of activating blood circulation to remove blood stasis.

Drugs with the efficacy of modifying rheological properties of blood, blood vessels and their interactions are denoted by "hemorheologicals". Drugs of anti-hyperviscosemia, anti-coagulants, anti-platelet drugs, anti-thrombotics, vasodilators, endothelial cell protectors and anti-arthrosclerosis should be considered as hemorheologicals due to the actions in keeping blood fluidity and in maintaining normal vascular functions. The studies in hemorheology indicate that a tendency of hyperviscosity, hypercoagulation and being prone to thrombosis is prevalent in the elderly. Hemorheologicals are importance for and aging and life-threatening diseases. Blood stasis syndrome is a common pathological syndrome in the elderly. In traditional Chinese medicine, the treatment for the syndrome is by herbs which activates blood circulation to remove blood stasis. The herbs have the efficacy of improving hemorheological events. Therefore, the herbs are the source for developing hemorheologicals. Ligustrazine isolated from Chuangxiong is an example. It showed significant inhibition on shear induced platelet aggregation and on platelet intracellular calcium demonstrated by laser confocal microscope.