The present paper aims to investigate the physicochemical quality of pharmaceutical drugs acquired and distributed by the Basic Pharmacy of the city of Cascavel-Paraná State. During the period between June 2004 and March 2006, samples of eight batches of acetylsalicylic acid 100 mg produced by two laboratories were analyzed. Following the techniques and specifications established by official compendiums, physicochemical tests of disintegration, dissolution, hardness, friability, uniformity of mass, content and limit of free acetylsalicylic acid were carried out. All the analyzed products presented quality deviations. All the six batches produced by one of the laboratories failed in the punctual dissolution test. The dissolution profile test confirmed such results, showing that these six batches cannot be considered equivalent to the branded drug.Colegio de Farmacéuticos de la Provincia de Buenos Aire