NEW MATERIAL:A compound of formula I (R , R are alkyl, cycloalkyl; R through R are H, lower alkyl, cycloalkyl, aralkyl, pyridyl; X is O, S; n1, n2 are 1 to 6) or its salt. EXAMPLE:1,3-Bis[[1-cycloheptyl-3-(2,4-difluorophenyl)ureido]methyl]ben zene. USE:Acyl-coenzyme A cholesterol acyltransferase inhibitor. It has an action to reduce lipids and simultaneously can be used for treating diseases relating to arteriosclerosis, for example cerebral infarction, transient ischemic attack and stenocardia. PREPARATION:The reaction of a diamine of formula II with an isocyanate or isothiocyanate of the formula: R NCX or R NCX (R , R are H, lower alkyl, cycloalkyl X is O or S) in an inert solvent at room temperature or with heat gives a compound of formula I (R , R are H).