The present invention aims to provide for the treatment of hyperlipidemia, arteriosclerosis and hyper-remnant-emia, and to inhibit remnant lipoportein production by adminsetering an inhibitor of CEPT (cholesteryl ester transfer protein). Said inhibitor is a compound selected from the group cosisting of compounds of formula I to fomula XXIII, and compounds selected from the group consisting of JTT-705, CP-529414, SC-795, SC-744, SC-554, SC-71952, SC-56960, SC-57201, PD-140195, WK-5341A, WK-5344B, CETI-1 (CETP Vaccine), BM99-1 and BM99-2.