A compound of chemical formula (I) and its pharmaceutically acceptable salt: ##STR1## wherein X and Y are each hydrogen, halogen, C.sub.1 -C.sub.6 alkyl, halosubstituted C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.6 alkylthio, C.sub.1 -C.sub.6 alkylsulfinyl, C.sub.1 -C.sub.6 alkylsulfonyl, or tri(C.sub.1 -C.sub.6 alkyl)silyl; Ar.sup.1 and Ar.sup.2 are each independently aryl or heteroaryl, optionally substituted by halogen; A is --CO-- or -(CH.sub.2)-; Z-A- is at the 2 or 3 position on the quinuclidine ring; and Z is --OH, C.sub.1 -C.sub.6 alkoxy, NR.sup.1 R.sup.2 or the like. Representative compounds are (3S,4R,5S,6S)-5-�3,5-bis(trifluoromethyl)-benzyloxy!-N,N-dimethyl-6-diphenylmethyl-1-azabicyclo�2.2.2!octan-3-carboxamide, and -3-carboxylic acid. These novel benzyloxyquinuclidines are active as substance P receptor antagonists and are thus useful for treating gastrointestinal disorders, central nervous system disorders, allergy, inflammatory diseases, asthma, pain, emesis, migraine, urinary incontinence, or angiogenesis in mammals, especially humans.