The inhibitory fiber against virulence factors production of the present invention is an inhibitory fiber against virulence factors production comprising a fiber and an inhibitor of virulence factors production fixed to the fiber by chemical bonding. The inhibitor of virulence factors production includes at least one compound selected from the group consisting of a phosphate group-containing compound, a carboxylic acid group-containing compound, and a ketone group-containing compound. The production method of the present invention is a method for producing an inhibitory fiber against virulence factors production comprising a fiber and an inhibitor of virulence factors production fixed to the fiber by chemical bonding. The method comprises: irradiating the fiber with an electron beam and bringing into contact with the fiber at least one compound selected from the group consisting of a phosphate group-containing compound, a carboxylic acid group-containing compound, and a ketone group-containing compound to chemically bond the at least one compound to the fiber. Another production method of the present invention is a method for producing an inhibitory fiber against virulence factors production comprising a cellulose fiber and an inhibitor of virulence factors production fixed to the fiber by chemical bonding. The method comprises: bringing an aqueous solution containing phosphoric acid and urea into contact with the cellulose fiber to chemically bond phosphoric ester to the cellulose fiber.
