Salicylic acid is used in many pharmaceutical and cosmetic formulations. In this study, salicylic acid (SA), three impurities: 4-hydroxybenzoic acid (4HBA), 4-hydroxyisophthalic acid (4HIPA), phenol (PHE), and two metabolites: gentisic acid (GA), salicyiglycine (SG) were chromatographed on both octadecylsilica (ODS) and phenyl high-performance liquid chromatography (HPLC) columns with UV detection. The effects of mobile phase pH and the addition of beta-cyclodextrin to the mobile phase were investigated. Selectivity, resolution, and peak shape are discussed. Linearity, sensitivity, and precision studies were conducted. The phenyl column was compared to the ODS column for impurities testing of salicylic acid. Commercial products (a gel and a collodion) were assayed for salicylic acid using the proposed methodology. (C) 1998 Elsevier Science B.V. All rights reserved.