The 8-hydroxy-2'-deoxyguanosine (8-OHdG) is a DNA base modified by reactive oxygen species (NOS). The 8-OHdG has been shown to be generated in the brain during ischemia-reperfusion. We performed the immunohistochemical study of 8-OHdG in the brains of autopsied specimens. Age had a statistically significantly negative correlation with 8-OHdG immunoreactivity in glial cells. The 8-OHdG immunoreactivity in glial cells was not increased in the surrounding border of the infarction compared with the non-ischemic areas in the same cases. There was no statistically significant difference in the disease-free areas between infarction and the age-matched control cases. This indicates that 8-OHdG immunoreactivity may not be a sensitive tool to evaluate the infarction injury in human autopsied specimens.