Abstract:Our observation shows that out of 102 kinds of Chinese medicinal herbs tested, 17 have remarkable antimutagenic effect on the mutation induced by aflatoxin B1. in Ames test. Among the 17 herbs Glycyrrhiza uralensis, Bupleurm chinense, Portulaca grandiflora and Cnidium monnieri have been found in other tests to be effective against mutagenesis induced by cyclophosphamide in mice.