PURPOSE: To provide a drug composition comprising a compound of a specific structure as the effective component which is particularly useful as the anti- tumor agents for anxiety, emesis, etc., caused by cytotoxic drugs and radiotherapy and further useful in treating irritable bowel syndrome, etc.

CONSTITUTION: A drug composition comprises a compound of the formula Ar-COnY-Z [wherein Ar is a group of formula I or formula II (wherein R1 and R2 are each H, a halogen or the like; X is CH2, -O- or the like; and R4-R1 are each H, hydroxyl or the like, with proviso that one of R4-R1 is other than H); Y is -O- or -NH-; Z is a group of formula III or formula IV (wherein n is 2-4; and R8 is H, 1-7C alkyl or the like) or the like; and with the proviso that when Ar is a group of formula II and Y is-NH-, Z is a group of formula IV or the like and is excluded the case where Ar is a group of formula I; R1 and R2 are both H; X is NH; Y is -O-; Z is a group of formula III; n is 2; and R8 is CH3] or a salt thereof and a carrier. As the compound of formula I, e.g. 3,5-dichloro-{3α-[8-methyl-8-azabicyclo (3,2,1)octyl]}-benzoate, etc. can be mentioned.