Three sets of flasks, each flask containing 15 gm. of green peas and 15 ml. of corn steep-casein medium, were inoculated with about 1,000 detoxified spores of C. botulinum, Types A and B, per flask. The pH was 6.6. One flask in each set was untreated. Rutin, quercetin, and quercitrin were added to give concs. ranging from 60 to 1600 ppm. The flasks were heated at 100[degree]C for 5 min. and incubated anaerobically for 10 days at 23 [degree]C. Sterile filtrates were prepared and tested for toxin by inoculating 0.2 ml. amts. into mice. Rutin in concs. up to 1,000 ppm. did not prevent growth or alter toxin production. Quercitrin was effective only in concs. of 1,000 ppm. Quercetin had a marked effect, amts. of 80-160 ppm. preventing toxicity. The action is antibacterial. Concs. of quercetin as high as 1,000 ppm. failed to inactivate preformed toxin in 72 hrs.