To evaluate the effect of steroid and alpha adrenergic blockade in experimental spinal cord trauma, pathological change was observed after 500 gm-cm force was impacted on the exposed cord of the 30 Mongoreal adult dogs. The progression of the pathological changes was compared in time lag with the groups of steroid adminstered and phenoxybenzamine treatment. In the group of the spinal cord trauma without treatment, histopathological findings were classical evolution namely from the central hemorrhage and necrosis to peripheral involvement up to amorphous necrotic pattern of entire cord at 24 hours preparation. In the steroid therapy group after the trauma, the pathological changes were confined in the gray matter around and posterior portion of the central canal in all intervals. Moreover the edematous changes and hemorrhagic necrosis were far less severe than the group without treatment. Although the pathologic change was somewhat less severe in the group which received phenoxybenzamine prior to the trauma than the group administered phenoxybenzamine afterward, these group revealed much severe edema and hemorrhagic necrosis than steroid therapy group. The pathologic change, however, in the groups which received phenoxybenzamine was less severe than the group of the spinal cord trauma without treatment.