Gamma irradiation was applied to Angelicae gigantis radix and Aloe to improve their hygienic quality. The effective dose of irradiation was 7 kGy in Angelicae gigantis radlx and 5 kGy in Aloe for the sterilization of all contaminated microorganisms tested. After 8 months of storage at room temperature, no growth of microorganisms was observed in the irradiated products. The safety of these products were evaluated by Salmonella typhimurium reversion assay and in vivo micronucleus assay using mouse bone marrow cells. They were negative in the bacterial reversion assay with S. typhimurium TA 98, TA100, TA1535 and TA1537. In the in vivo mouse micronucleus assay, they did not show any clastogenic effect at all doses tested. These results indicate that the gamma irradiation of Angelicae gigantis radix at 12 kGy and of Aloe at 10 kGy have no genotoxic effects under these experimental conditions.