PURPOSE: To obtain the subject lowering agent, containing a condensed ring compound represented by a specific formula and useful for preventing and treating hyperlipemia, above all, preventing and treating hypertriglyceridemia according to a new mode of action.

CONSTITUTION: This lowering agent contains a compound of the formula [R1 is H or a (substituted)hydrocarbon; R2 and R3 are each H, a (substituted) hydrocarbon or a (substituted)heterocyclic ring; X' is a (esterified)carboxyl, a (substituted)carbamoyl, a (substituted)OH, a (substituted)amino or a (substituted)heterocyclic ring having H which can be deprotonated; ring A is a (substituted)benzene ring or a (substituted)heterocyclic ring; ring J' is a 7- to an 8-membered heterocyclic ring containing ≤3 hetero-atoms as ring constituent atoms], preferably (3R,5S)-7-chloro-5-(2,3-dimethoxyphenyl)-1-neopentyl-2- oxo-1,2,3,5-tetrahydro-4,1-benzoxazepine-3-acetic acid or its pharmaceutically permissible salt (preferably an Na salt).