Abstract:Geng Sai Tong(GST) was orally administrated to dogs, rats and mice. Then the volume of blood flow in carotid and intra-carotid of anesthetic dogs, and in carotid of anesthetic rats was determined. The water content and the blood vessel permeability of the brain of rats with brain ischemia were checked, The living time of mice under the condition of brain ischemia and without oxygen, and the time of blood coagulation of mice was also checked, The results showed that GST can markedly increase the volume of blood flow in the brain of dogs and rats, and can significantly decrease lift of the water content and the blood vessel permeability of the brain of the rats with brain ischemia, and can markedly prolongate the living time of mice under the condition of brain ischemia and without oxygen and the time of blood coagulation in mice.