An aggregation parameter-based analytical approach, the surfactant-dye binding degree SDBD method, was used, for the first time, to determine aromatic hydrotropic compounds. The anionic dye Coomassie Brilliant Blue G CBBG was used as inductor of didodecyldimethylammonium bromide DDABr aggregates, whose formation was monitored from changes in the spectral features of the dye. Interactions between hydrotrope and DDABr molecules resulted in a decrease of the degree of binding of the cationic surfactant to CBBG, which was proportional to the concentration of hydrotrope in the aqueous solution. The CBBG–DDABr–hydrotrope chemical system was found to fit to the mathematical expression previously derived for the determination of amphiphilic compounds. The hydrotrope–surfactant bond strength determined the sensitivity achieved for the determination of hydrotropic compounds, which was highly dependent on the molecular structure of the analyte. The high precision the relative standard deviation for 7 mg l−1of salicylic acid was 0.8, rapidity measurements were performed in a few minutes and low cost in both instrumentation and reactants of the proposed method, made it especially suitable for quality control. The practical analytical applicability of the SDBD method for the control of hydrotropic drugs in pharmaceutical preparations was demonstrated by quantifying salicylic acid and acetyl salicylic acid in liquid solutions and solid tablets, granulates, unguents, gels and creams samples, which were directly analyzed after dissolution of the samples.