The invention relates to a method of treatment and/or prophylaxis of diseases and conditions mediated by peroxysome proliferator-activated receptor gamma (PPAR.gamma.) in a mammal subject in need thereof, said method comprising administration to said mammal a compound of formula (I) or a pharmaceutically acceptable salt thereof in a therapeutically or prophylactically effective amount ##STR00001## wherein in formula (I) W represents a COOH group or its bioisosters, or COO--C.sub.1-C.sub.4-alkyl group; Y represents NH or N--C.sub.1-C.sub.10-alkyl; Z represents NH, N--C.sub.1-C.sub.10-alkyl, N-aryl, N-heteroaryl, S, or O; X represents O, S, NH, N--C.sub.1-C.sub.10-alkyl, N-aryl, NSO.sub.2--C.sub.1-C.sub.10-alkyl, N--SO.sub.2-aryl, or N S0.sub.2-heteroaryl; R.sub.1 to R.sub.6 each independently represents a hydrogen atom or a substituent defined in the description; A is as defined in the description; n represents an integer from 0 to 4, inclusive. The compounds of formula (I) are the ligands of PPAR-gamma receptor.