Abstract: A novel naphthyridine compound represented by the general formula (1): wherein R1, R2 and R3 are independently a hydrogen atom, a lower alkyl group or the like, or R1 and R2, or R2 and R3, when taken together, form a cyclic group; each of X and Y is a methylene or ethylene group; Z is a phenyl group, a substituted phenyl group or the like; A is a hydrogen atom, a lower alkyl group or the like; and G is an acyl group, shows antagonism for tachykinin receptors and is useful as a prophylactic or therapeutic agent for diseases for which the tachykinin receptors are considered to be responsible. A specific example of such a compound is 2-[(−)-4-(N-benzoyl-N-methyl)amino-3-(3,4-dichlorophenyl)butyl]-10-acetylamino-1,2,3,4-tetrahydro-benzo[b][1,6]naphthyridine.