This short review focuses on the chemical events related to DNA damage induced by free
radicals. Diffusible hydroxyl radicals (HO) are able to react with either the sugar units by
hydrogen abstraction or with the base moieties by addition. Selectively generated carbon-
centred radicals at C1′, C4′ and C5′ in model nucleosides or oligonucleotides and their
subsequent fate under aerobic or anoxic condition are discussed by rationalisation of the
available kinetic data. Reaction paths for the formation of nucleobase modifications such as …