Patent ID: 8133991

Claim:
A method for inactivating allergen comprising treating an allergen-existing environment with an allergen inactivating agent comprising a polysaccharide derivative as its effective component, wherein the polysaccharide derivative has a cellulose ether as its backbone, and some or all of hydrogen atoms in the hydroxy group of the polysaccharide derivative are substituted by a group represented by formula (I): -E 1 -(OA) n -E 2 -R (1) wherein E 1 represents an alkylene containing 1 to 6 carbon atoms optionally substituted with a hydroxy group or an oxo group; n represents a number of 0 to 50; A independently represents an alkylene containing 1 to 6 carbon atoms, the number of A being n; E 2 represents an ether bond or an oxycarbonyl group; R represents an alkyl group containing 4 to 30 carbon atoms optionally substituted with a hydroxy group, a sulfoalkyl group containing 1 to 5 carbon atoms optionally substituted with a hydroxy group, or a salt thereof, comprising spraying the polysaccharide derivative in an allergen-existing environment.