The problem addressed by the present invention is to provide a novel bactericide using an oxidative stress-dependent foreign material elimination response by causing the collapse of SodB-dependent antioxidative activity in gram-negative pathogenic bacteria such as Helicobacter pylori. The present invention provides a bactericide dependent on a host foreign material elimination response in response to a gram-negative pathogenic bacteria such as Helicobacter pylori and resulting from a FecA1-compatible compound selected from nordihydroguaiaretic acid, secoisolariciresinol, 2,3,4,4'-tetrahydroxydiphenylmethane, terameprocol, phyllanthine, and the like.
