Contact dermatitis is by far the most frequently reported occupational disease, with irritant dermatitis accounting for up to 80% of all cases. A wide variety of materials are capable of causing skin inflammation including soaps, cosmetics, pesticides, organic dyes, solvents and industrial chemicals and wastes. Skin irritation results from a complex series of events involving the development of an inflammatory response at the site of exposure. Cytokines are a family of proteins and glycoproteins that regulate immune and inflammatory responses; many are produced by epidermal cells. The present study examines the response of mouse epidermal strips to the cutaneous irritant sodium dodecyl sulphate (SDS). A time-dependent relationship was established for the release of the cytokine tumour necrosis factor-alpha, from epidermal keratinocytes after treatment with 20% SDS. The potential value of this methodology for the detection of cutaneous irritants has been established. The utility of the approach for the identification in vitro of other materials of known in vivo irritant potential will be investigated.