The drug release property from the coated tablets which contain 291mg of acetylsalicylic acid were estimated from comparison of the blood level and the urinary excretions after oral ingestion of coated tablets and noncoated tablet in human. The coating materials are 2-methyl-5-vinylpyridine-methylacrylic acid copolymer(MPM), dimethyl aminoethyl methacrylate methyl methacrylate copolymer(EE), polyvinyl acetal diethyl aminoacetate(AEA), and shellac. Each of 7 subjects ingested 873mg of acetylsaliylic acid. All tablets are coated approximately $3.5{pm}0.5%(w/w)$ per tablet with each of the coating materials and met K.P.II. standard for potency and disintegration time. The availability was decreased in the following order:MPM coated tablets>EE coated tablets>AEA coated tablets>> shellac coated tablets.