The invention provides novel anilide compounds and pharmaceutical compositions comprising them. The invention relates to compounds of a formula: where Ar is an optionally-substituted aryl group; R4 and R5 are the same or different, and each is a hydrogen atom, a lower alkyl group, or a lower alkoxy group; and R4 and R5 may together form a lower alkylene group of which one or more methylene moieties may optionally be substituted by oxygen and/or sulfur atoms; X is —NH—, or oxygen or sulfur atom; Y is —NH—, an oxygen or sulfur atom, or a sulfoxide or sulfone group; Z is a single bond, or —NH6—; R6 represents a hydrogen atom or a lower alkylene group; and n is an integer of from 0 to 15; and their salts and solvates. The compounds of the invention are useful as pharmaceutical compositions, especially as acyl coenzyme A cholesterol acyltransferase (ACAT) inhibitors.