This experiment was performed to determine the safety of the Korean red ginseng irradiated with gamma rays with respect to genotoxicity. Ethanol extracts of the 5 and 10 kGy gamma-irradiated red ginseng were examined in two short-term in vitro tests : (1) Salmonella typhimurium reversion assay(Ames test) in strain TA 98, TA 100 and TA 102 (2) Micronucleus test in cultured Chinese hamster ovary(CHO) cells. No mutagenicity was detected in the two assays with or without metabolic activation. It was suggested that the Korean red ginseng irradiated with gamma rays did not cause genotoxicity in vitro. Further tests of genotoxicity in vivo, chronic and reproductive toxicity should be carried out to determine whether it is safe to irradiate Korean red ginseng with practical doses of gamma rays.