Interleukin 6 (IL-6) is an endogenous cytokine with multiple biological functions, including amplification of the inflammatory response. Recombinant human IL-6, administered as part of a chemotherapeutic regimen, has recently been shown to cause regression of certain types of malignant tumours. We report a patient who developed a cutaneous eruption consisting of coalescent, erythematous, scaling macules and papules after administration of recombinant human IL-6, given as part of her chemotherapy for ductal carcinoma of the breast.