PROBLEM TO BE SOLVED: To provide safely ingestible DNA damage inhibiting agents comprising oligosaccharides as effective components.SOLUTION: A DNA damage inhibiting agent of the invention comprises, as the effective component, an oligosaccharide comprised of 1-10 molecules of monosaccharides, mainly of mannose. In certain embodiments, the DNA damage inhibiting agent inhibits production of 8-hydroxy-2'-deoxyguanosine (8-OHdG). In certain embodiment, the 1-10 molecules of monosaccharides constituting the oligosaccharide are selected from the group consisting of mannose, glucose, galactose and fructose.
