To obtain a composition for processing a fiber product, which can impart a washing-resisting property or an anti-microbial-deodorant property to clothes and the other fiber products at home or at a laundry, can further impart properties such as a good moisture-absorbing property, a good touch, a good bulky touch and a good comfort, and can inform a time for again imparting an anti-microbial-deodorant treatment, when the imparted effects are gradually deteriorated due to many repeated washing treatments, and to provide a method for processing the fiber product with the composition for processing the fiber product.

This composition for processing the fiber product is characterized by comprising an aqueous solution containing (A) a hydrolyzed protein silylation product, (B) a protein and (C) chitosan as essential components and further containing (D) a plant-originated active ingredient. The method for processing the fiber product is characterized by treating the fiber product with the composition for processing the fiber product.