Bruceanol B, isolated from a soil microbe strain DS4, generated oxygen radicals in Bacillus subtilis lysates. Bruceanol B inhibited the trafficking of viral glycoprotein in virus-infected baby hamster kidney (BHK) cells. Bruceanol B also effectively inhibited syncytium formation in a dose-dependent manner. However, glycoprotein synthesis was not affected by the compound. Results indicate that bruceanol B generating oxygen radical has inhibitory activity in the trafficking of viral glycoprotein of BHK cell.