The DNA repair ability of a cell is vital to the integrity of its genome and thus to its normal functioning and that of the organism. The repair-enhancing property of polysaccharides isolated from Ganoderma lucidum which belongs to the polyporaceae family was determined by comet assay in human peripheral blood leukocytes. Comet parameters were studied at 2 Gy gamma irradiation with 15 min intervals. The comet parameters after 2 Gy exposures to ?-radiation were reduced to nearly normal levels after 120 min of exposure. The polysaccharides from G. lucidum enhance the repair process, which is a promising approach for protection from radiation exposure, but a detailed study of the molecular mechanism is needed for further application.