The present invention relates to piperidine derivatives of formula (I): ##STR00001## wherein R, R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, X, Y, m and n are as defined herein; and pharmaceutically acceptable salts and solvates thereof; the process for their preparation and their use in the treatment of conditions mediated by tachykinins.