Primary Sjögren's syndrome is a systemic autoimmune exocrinopathy characterized by a lymphoplasmacytic infiltrate and destruction of salivary and lacrimal glandular tissues. There is no widely accepted or effective systemic therapy for this disorder. The purpose of this 6-month randomized, double-blinded, placebo-controlled study was to examine the effects of prednisone (30 mg, alternate days), piroxicam (20 mg, daily), or placebo on the salivary, lacrimal and immunologic alterations of primary Sjögren's syndrome. Eight patients were enrolled in each group. Salivary and lacrimal function were assessed at entry and at the completion of treatment. Labial minor salivary gland tissue was obtained at these times and examined for intensity of infiltration (focus scores) and for the relative proportion of glandular elements. Serologic and subjective evaluations were done as well, and patients were monitored for therapy-related side effects. Neither active treatment led to significant improvement in salivary or lacrimal function, although prednisone improved salivary flow in selected patients and was associated with positive subjective responses. Prednisone also significantly decreased the serum total protein, IgG, IgA, and sedimentation rate and increased the white cell count. There were no significant alterations in either focus scores or the percentage of glandular component tissues of minor glands with either active treatment. This study demonstrated that 6 months of prednisone or piroxicam at the doses utilized failed to improve the histological or functional parameters of salivary and lacrimal glands in primary Sjögren's syndrome.