An early event during the induction of skin sensitization is the production by keratinocytes (kc) of cytokines. Considering the role of kc in skin inflammatory and immune responses, we investigated the effect of three skin allergens (oxazolone, nickel sulfate and mixture of methyisothiazolinone and methylcholoisothiazolone) on IL-1 alpha production by a murine kc cell line (HEL30). Confluent cells were treated for different times with various concentrations of oxazolone, NiSO4 and mixture of methyisothiazolinone and methylcholoisothiazolone. IL-1 alpha was measured by ELISA both in conditioned media and cell-associated. All chemicals were able to induce a dose-response production of IL-1 alpha. This increase was related to an increase in protein synthesis as measured by 3H-leucine incorporation. At high concentrations all chemicals were cytotoxic as measured by LDH release. In the same cell system we also measured the effect of lanolin, a non irritant compound, on IL-1 alpha release. Even at the concentration of 300 micrograms/ml no IL-1 alpha release could be detected in the conditioned media. We have previously found a good rank correlation between in vitro surfactants induced IL-1 alpha release and in vivo Draize test. We now extend the possibility to use IL-1 alpha production for preliminary screening of chemicals for their irritative/allergenic potential, reducing the need for in vivo models.