Abstract: Purpose and methods: The mutagenicity of No.Ⅱdrug was examined using Ames test, CHO-K cell chromosome aberration test and micronucleus test. Results: No.Ⅱ drug in the dose range of 1～5 000 μg / plate did not increase the number of reversion mutation in any of the 4 strains with or without S 9 in Ames test. The frequencies of micronuclear cell(MNCF) in PCE did not increase with dose of 25～125 mg / kg in micronucleus test. In CHO-K cell chromosome aberration test, the result was suspiciously positive because the frequency of chromosome aberration increased to 8 ％ with the dose of 250 μg / ml with S 9. Conclusion: The results of No.Ⅱ drug in Ames test and micronucleus test were negative, and at higher dose in chromosome aberration test the result was suspiciously positive.

Key words: No.Ⅱ drug, Ames test, Micronucleus, Chromosome aberration