PURPOSE: An antilipemic agent, containing a specific thienyloxazolylacetic acid derivative as an active constituent, and having improved reducing action on cholesterol in blood serum, reducing action on triglyceride in the blood serum and inhibitory action on agglutination of blood platelets without side effects, e.g. hepatic functin disorder.

CONSTITUTION: An antilipemic agent containing a thienyloxazolylacetic acid derivative expressed by formula I (ring A is phenyl or halogen-substituted phenyl; R1 is H or lower alkyl) or a pharmacologically acceptable salt thereof e.g. ethyl 2-[2-(4-fluorophenyl)-5-(3-thienyl)-4-oxazolyl]acetate, as an active constituent. The compound is obtained by subjecting a 3-benzoylaminopropionic acid derivative expressed by formula II (R2 is lower alkyl) to the ring closing reaction through dehydration in the presence of a dehydrating agent in a solvent to form the aimed compound expressed by formula I (R1 is lower alkyl). The daily dose thereof is preferably 5W15mg/kg body weight expressed in terms of the active constituent.