The fish meat of yellowtail was broiled until the surface temperature came up to 260°C before or after the immersing treatment (for 20min at room temperature) in the gel-filtrated fractions of cabbage juice. Then the effect of each fraction on mutagenicity of the broiled fish was examined by Ames method using Salmonella typhimurium TA 98 in the presence of S-9 mix. Cabbage juice was separated into a high molecular weight fraction (F- I) and three low molecular weight fractions (FII-1, F- II-2 and F- II-3) by a gel-filtration using Sephadex G-25. The extract from the broiled fish meat, which was immersed in distilled water instead of cabbage juice fraction, showed high mutagenicity and the mutagenicity was strongly inhibited by addition of F- I and F- II-1 fractions. When the fish meat was broiled after the immersing treatment in each fraction, F- I, F- II-2 and FII-3 fractions showed antimutagenicity, especially, the lowest molecular weight fraction, F- II-3, had higher antimutagenicity than the other fractions and F-II-3 heated at 1006°C for 20min had also high antimutagenicity. These results suggested that some factors in cabbage juice have not only the antimutagenicity on mutagens of charred materials produced on the surface of broiled fish, but also have inhibitory action on the formation of mutagens in charred materials.