Drugs useful for the treatment and prevention of hyperlipidemia, moreover drugs useful for the treatment and prevention of cholestasis-caused hepatopathy, particularly primary biliary cirrhosis and primary sclerosing cholangitis, and drugs for the treatment and prevention of obesity, fatty liver and steatohepatitis, containing as active ingredients benzothiazepine compounds having a thioamide bond and a quaternary ammonium substituent, represented by formula (1) below are provided. ##STR00001## Also, drugs containing ileal bile acid transporter inhibiting compounds as active ingredients for the treatment and prevention of cholestasis-caused hepatopathy are provided.