Mast cells are well known effector cells not only in allergic but also in diverse acute and chronic inflammatory diseases. We have shown previously that these cells produce a broad spectrum of cytokines which might contribute to mast cell-dependent pathology. In the present study, we have investigated the influence of four potent glucocorticoids, methylprednisolone-aceponate, methylprednisolone-17-propionate, prednicarbate, and betametasone valerate (105M-10-9M), on the IL-1β, IL-3, IL-8, and tumor necrosis factor α secretion of the HMC-1 mast cell line as measured by ELISA. All four glucocorticoids caused a comparable dose- and time-dependent inhibition of cytokine release from HMC-1 cells stimulated for 24 h with phorbol 12-myristate 13-acetate 25 ng/ml and calcium ionophore 2 × 10-7M. These results shed further light on the mechanisms involved in antiinflammatory effects of glucocorticoids in allergic inflammation.