Drugs that affect the production or action, or both, of the pleiotropic inflammatory cytokine interleukin-1 (IL-1) are predicted to have a significant impact on a variety of human diseases. The biochemical properties of IL-1 and the IL-1 receptor antagonist, the mechanism for their production, and the factors that regulate their release are discussed here. The association of IL-1 with various disease states is also reviewed. Various classes of drugs that can be used to manipulate the production of IL-1 and IL- I receptor antagonist are described. Interferon-alpha2b is a potent inhibitor in vitro of the induction of IL-1 and tumor necrosis factor by IL-1 and can induce high circulating levels of the anti-inflammatory soluble tumor necrosis factor receptor and IL-1 receptor antagonist in humans. Thus, interferon-alpha2b exhibits potent anti-inflammatory effects.