An atrovastatin-containing coated preparation characterized by comprising a solid material comprising atrovastatin, a pharmacologically acceptable salt thereof or a solvate of atrovastatin or the pharmacologically acceptable salt and a coating agent comprising a poly(vinyl alcohol) copolymer, wherein the solid material is coated with the coating agent and a method for preventing the production of an analogue of atrovastatin, a pharmacologically acceptable salt thereof or a solvate of atrovastatin or the pharmacologically acceptable salt and a method for stabilizing atrovastatin, a pharmacologically acceptable salt thereof or a solvate of atrovastatin or the pharmacologically acceptable salt, each of which is characterized by coating the solid material with a coating agent comprising a poly(vinyl alcohol) copolymer.
