In the present studies, decursinol angelate, decursin isolated from Angelica gignatis radix and oil fraction of Cnidii rhizoma was analyzed by normal phase HPLC and GC/MS respectively. The standardized water extracts of Angelica gignatis radix, Cnidii rhizoma and its complex named Gung-gui-tang was tested the anti mutagenic effects by in vitro genotoxicity using Salmonella reversion assay (Ames test) and micronucleus test in chinese hamster ovary(CHO) cells. Angelica gignatis radix, Cnidii rhizoma and Gung-gui-tang was not exhibited the antimutagenic effects in the Salmonella reversion assays with or without metabolic activation. However, the micronucleus test assays, Angelica gignatis radix and Gung-gui-tang was showed the antimutagenic effects significantly. The maximum inhibition observed with Gung-gui-tang was reduced by 59% in the micronucleus test without metabolic activation. In this paper, results are presented on the availability of potential antimutagenic activity of the water extracts of Gung-gui-tang.