Abstract Triamcinolone acetonide, a new corticosteroid which has been suggested as a highly active topical agent in the treatment of certain acute and chronic lesions of the oral mucous membranes, was studied with respect to its possible systemic actions. In order to determine any undesirable effects incident to topical therapy, we undertook detailed blood chemistry, hematologic, and urine studies in eleven patients treated with this corticosteroid. A comparative study of the before- and after-treatment blood and urine test values following the five-day period of drug therapy (including 1 mg. per day of the active agent, triamcinolone acetonide) did not reveal any discernible or noteworthy deviations. All test findings remained within the accepted normal range. Where posttherapy deviations within the normal range were found, no consistent pattern was evident.