Abstract: The systematic and local concentrations of piroxicam after oral and transdermaladministration were determined and compared. Mice were randomly grouped,and oral suspensions(0.72 mg· ml^-1) or transdermal gels 1 mg· ml^-1 were given,Systematic concentration (C_s)andlocal concentration(C₁) of the drug in each mouse were determined by HPLC method, Aftertranedermal administration of 0.25 mg of piroxicam gels C_max(s)=8.06μg· ml-1 and AUC^0～24_(s)=58.36μg·h·ml^-1 were obtained, whereas after oral administration of 0.026 mg·10g^-1 bodyweight of piroxicam suspensions C_max(s) was 36.82 μg· ml^-1 and AU^0～24_(s)was 155.59μg·h·ml^-1 . The C₁/C_s ratio(0. 01) through oral route was far lower than the C₁/C_s ratio (0.13)through transdermal route, The area under local concentration—time curve(15. 85μg·h·ml^-1)calculated from transdermal administration was much higher than that from oral administration (1.93μg·h·ml^-1).So,it seems to be unreasonable that only serum concentration is taken as a criterion forbioavailability test of piroxicam for local dosage forms,the local drug concentration should also beinvestigated and evaluated.