Many derivatives of imidazole and benzimidazole are widely used in industry, agriculture, photography, as well as in medical practice [1-4, 6, 9-11, 13]. Most of them have been studied for toxicity. The mutagenic activity of these compounds still has been little investigated. It was shown that benzimidazole does not show mutagenic activity on Drosophila melano~ aster [2] but for Salmonella typhimurium it is a mutagen [12]. It is not ...