Synonyms: 4-Hydroxybenzoic Acid, Ethyl Parahydroxybenzoate Imp. A (EP), Butyl Parahydroxybenzoate Imp. A (EP), Propyl Parahydroxybenzoate Imp. A (EP), Methyl Parahydroxybenzoate Imp. A (EP), Acetylsalicylic Acid Imp. A (EP), Salicylic Acid Imp. A (EP), 4-Carboxyphenol, 4-Hydroxybenzoic acid, NSC 4961, Paraben-acid, p-Carboxyphenol, p-Hydroxybenzoic acid, p-Salicylic acid