The aim of this study is to investigate the effects of experimental cold brain injury on blood-brain barrier integrity, on brain oedema formation, and on lipid peroxidation and to compare the results between the aged and young rats. Cold brain injury was used to create a standard model of brain trauma in old and young rats. Disruption of the blood-brain barrier was analyzed by Evans blue method. Them values of cerebral water content were calculated by using the fresh and dry weights of the cerebral hemispheres. Lipid peroxidation was assessed by measuring the tissue content of malonyl dialdehyde.