Due to various confounding factors, namely dietary contribution and cell death, measurement of urinary 8-oxo-2'-deoxyguanosine (8-oxodG) has long been considered to be no more than a marker of generalised oxidative stress. Indeed, the action of no single enzyme has been reported to excise 8-oxodG from DNA. However, analysis of recent research has suggested that these confounders may be circumvented, which, combined from work from the authors' laboratory, indicates that urinary 8-oxodG has the potential to become a most important marker of oxidative damage to, and repair of, DNA.