Abstract: An allergen reducing composition capable of reducing allergens such as mites and cedar pollen and causes less coloring of an allergen reduction target; a spray agent using the allergen reducing composition; a surface treatment agent using the allergen reducing composition; an allergen reducing method; an allergen reducing textile structure; and an allergen reducing architectural interior material. The allergen reducing composition contains: (A) one or more compounds selected from zinc salts and copper salts; and (B) one or more compounds selected from rare earth salts. The spray agent or the surface treatment agent contains the allergen reducing composition and water or a water-soluble solvent. An allergen reducing method involves using the above-mentioned allergen reducing composition in an environment where allergens are present. The textile structure is a textile structure processed by the allergen reducing composition.