Interleukin‐8 (IL‐8) belongs to a family of small, structurally related cytokines similar to platelet factor 4. It is produced by phagocytes and mesenchymal cells exposed to inflammatory stimuli (e.g., interleukin‐1 or tumor necrosis factor) and activates neutrophils inducing, chemotaxis, exocytosis and the respiratory burst. In vivo, IL‐8 elicits a massive neutrophil accumulation at the site of injection. Five neutrophil‐activating cytokines similar to IL‐8 in structure and function have been identified recently. IL‐8 and the related cytokines are produced in several tissues upon infection, inflammation, ischemia, trauma etc., and are thought to be the main cause of local noutrophil accumulation.