Amoxicillin is a widely prescribed aminopenicillin, primarily for oral use.1) Ninety percent of the administered dose is absorbed without molecular modifications.2) It provides human serum concentration ranging from 7.6 mg/ml to 10.8 mg/ml when 500 mg/p.o. is used 3,4) ; 15.1 mg/ml when 15.4 mg/kg/p.o. is used, 1) and 14.5 mg/ml when 40 mg/kg/p.o. is used.5) The serum concentrations in rats were 28 mg/ml and 13 mg/ml when amoxicillin doses of 40 mg/kg/p.o. and 7.0 mg/kg/p.o. were administered, respectively. 6,7)