The invention relates to the discovery that the addition of aromatic carboxylate ions inhibit protein instability caused by aromatic preservatives. Thus, the invention relates to compositions, (preferably aqueous compositions, comprising a protein, an aromatic preservative and aromatic carboxylate ions. The proteins remain stable and suitable for storage at ambient temperatures or lower, even in aqueous form. Preferably, the aqueous composition comprises a protein, a phenolic preservative and benzoate ions, wherein the pH of the composition is at least 1 unit greater than the pKa of benzoic acid. The invention also provides methods of reducing protein degradation by aromatic preservatives in an aqueous formulation of a protein susceptible to such degradation, comprising the step of adding aromatic carboxylate ions to the formulation wherein the formulation is maintained at a pH that is at least 1 unit greater than the pKa of the corresponding aromatic carboxylic acid.
