Abstract: The invention provides pharmaceutical compositions comprising hypolipidemically active derivatives of 1,2,4-triazolidine-3,5-diones, 1,3,5-triazabicyclo[3.1.0]hexane-2,4-diones, and 1,3,5-triazine-2,4(1H,3H)-diones in a pharmaceutically acceptable carrier for treating hyperlipidemia in mammals, particularly humans.

Abstract: A method of controlling hyperlipidemia in mammals which comprises adminstering to a mammal an amount effective to control hyperlipidemia of a compound having hypolipidemic activity and the structural formula: ##STR1## wherein R.sup.1 and R.sup.2, which may be the same or different provided both are not hydrogen when R.sup.3 is an alkenyl or cycloalkenyl group, are selected from the group consisting of hydrogen; alkyl of 1 to 18 carbons; substituted alkyl of 1 to 18 carbons; cycloalkyl of 4 to 10 ring carbon atoms; substituted cycloalky of 4 to 10 ring carbon stoms; alkoxy of 1 to 8 carbon atoms; amido; carbamoyl; acyloxy; alkoxycarbonyl; halogen, aryl and substituted aryl, or together R.sup.1 and R.sup.2 from a C.sub.3 to C.sub.7 alkylene group; andR.sup.3 is hydrogen; lower alkyl; substituted lower alkyl; cycloalkyl; substituted cyloalkyl; aryl; substituted aryl; a group --COR.sup.4 were R.sup.