Abstract: A method for selectively opening abnormal brain tissue capillaries of a mammal in order to allow selective passage of both low and high molecular weight neuropharmaceutical agents into abnormal brain tissue. The method utilizes direct infusion of bradykinin or bradykinin analog into the carotid artery. The dose of bradykinin or bradykinin analog is maintained at levels which provide opening of abnormal brain tissue capillaries without opening normal brain capillaries. The method is useful for introducing a wide variety of neuropharmaceutical agents selectively to brain tumors and other abnormal brain tissue.