The blue tetrazolium colorimetric assay has often been employed in the analysis of corticosteroids. However, the reaction between blue tetrazolium and corticosteroids partly depends on the apparent pH of the system. In an earlier study of the temperature dependence of the solubility and dissolution of triamcinolone acetonide in aqueous dissolution media (distilled water and 0.2-1.0 M potassium chloride solutions), pH was not considered. To determine the reliability of the data previously reported, the solubility of 14C-triamcinolone acetonide was determined by a radioisotopic method. The results of the analyses, using a liquid scintillation counting system, indicate that the steroid solubility is generally about 20% lower than that reported previously.