By means of stereoscopic microscopy morphologic observation was made on vascularization of the blood vessels during the progress of postexodontic wound healing in 37 mature dogs. Imagawa's Guttapercha Infusion Method was adapted and macroscopic and radiographic observations were combined. In the wounds of 86 normal tooth extractions more remarkable vascularization could be noticed in the wound openings than in the apical areas in the early postexodontic stage. During the period of 10 to 14 days after extraction gingival mucosa covered the wound and capillary vascularizations were completed. Tendency of vascularization in postexedontic wound healing was fundamentally identical with those of descriptions by Clark and Akita: capillary buds formed, capillary loops newly developed, and then capillary networks completed. In the wounds of 50 extractions with apical foci experimentally made, capillary networks were dense in the wound opening, while they were loosened in the apical areas with a distinct difference between them in the early postexodontic stage. In the later stages, however, vascularization seemed to show a tendency of slight delay in comparison with normal healthy controls. In adittion, the effect of gauze packing and insertion of penicillin dental cone upon the wound healing was investigated.