The process of hypothermia in the clinical setting has been practiced for 50 years and is known for its neuroprotective properties. This paper describes histopathological changes either by an ice sludge mimicking accidental hypothermia (S-group n=7) or by endovascular core-cooling (C-group n=7). Focal infi ltrates of neutrophilic granulocytes were found in fi ve of seven brains in the S-group and in one of seven brains in the C-group. These granulocytes were found in the arachnoids, in vessels, in vessel walls, and in the cerebral cortex. Fungi, bacteria, lymphocytes or plasma were not found.This experimental study, mimicking accidental hypothermia, reported histopathologic features of aseptic infl ammation. To our knowledge, such fi ndings have not been described in hypothermic animals or humans before. We suggest that a local infl ammatory response may be triggered in such cases of hypothermia.