In order to observe the histopathological changes with the progress of time after formation of bite-mark, experimental bite-marks were made in female rats and histopathological examinations were performed in the given sites immediately, 5 minutes, 10 minutes, 30 minutes, I hr., 4 hrs., 8 hrs., 12 hrs., 24 hrs., and 48 hrs, after injury. Results and Summary 1. Subcutaneous loose connective tissues and fatty layers were compressed immediately after formation of bite-marks, injured epithelia showed hydropic degeneration 5 minutes later. 2. Inflammatory cells emigrated into tissues with hemorrhages in the tissues after 10 minutes, and more increased centered around the blood vessels.- These distributed most densely in the tissues, after 12 hrs., thereafter, were decreased and distributed in various groups of crowdy appearances, after 48 hrs. 3. After 10 minutes, neutrophils emigrated into tissues and disappeared gradually with an appearance of monocytes. These disappeared completely, after 24 hrs. Lymphocytes and plasma cells were see n at 48 hrs. later. 4. Adherence of mast cells to injured sites occurred immediately, and which adhered to blood vessel walls of injured sites, after 10 minutes. 8 hrs. later, degranulation in emigrated inflammatory cells showed, and these degranulation disappeared gradually with a progress of time.