A study was designed to determine the inhibitory effect of chlorophyllin (11006921) against the mutagenic activity of different chemical compounds such as aflatoxin-B1 (1162658) (AFB1), 2- aminoanthracene (613138) (2AA), benzo(a)pyrene (50328) (BaP), N- methyl-N'-nitro-N-nitrosoguanidine (70257) (MNNG) and complex mixtures of airborne and diesel emission particles, coal dust, tobacco snuff, black pepper and red wine using the Salmonella- arabinose resistant forward mutation assay system. Various concentrations of each chemical and complex mixture extract were assayed for mutagenic activity with and/or without S9 in a preincubation test. One concentration of each chemical and complex mixture extract was then tested with various concentrations of chlorophyllin. Results indicated that chlorophyllin, at concentrations of 2.5 milligrams/plate or less, completely or almost completely inhibited the mutagenicity of 2AA, AFB2, BaP, MNNG, and solvent extracts of coal dust, diesel emission, and red wine. With concentrations from 1.25 to 5 milligrams/plate, chlorophyllin inhibited over 50% of the mutagenicity of airborne particles, tobacco snuff, and black pepper extracts. The authors conclude that these results further substantiate the antimutagenic efficacy of chlorophyllin against chemicals and complex mixtures.