Piperidine derivatives

Piperidine derivatives have the following general formula ÄIÜ: wherein A represents the following formula ÄAÜ: wherein m is 0 or 1, n is 1 or 2, X represents CH2, O or CH-CH3, R represents an unsubstituted or substituted phenyl group or an unsubstituted or substituted heterocyclic group, R1 and R2 may be the same or different and represent a hydrogen atom or a lower alkyl group, respectively, and R3 represents a hydrogen atom or a lower alkyl group, or pharmaceutically acceptable acid addition salts thereof which provide a non-peptidic antagonistic action against substance P and substance P antagonists having the above derivatives or salts as an effective component, are disclosed.