Interleukin-1 (IL-1) has been strongly implicated as an inflammatory mediator in anterior uveitis. Recently, solubilized receptors have been utilized to block the binding of viruses to cell membranes or to inhibit cytokine activity. We have tested the activity of an intravitreally injected soluble, human interleukin-1 receptor in a rabbit model of IL-1-induced inflammation. 3 ug of the soluble receptor markedly inhibited both the cellular infiltration and the protein extravasation that followed 6 hours after an intravitreal injection of 10.5 ng of recombinant human interleukin-1 alpha. The efficacy of the soluble receptor was less marked 24 hours after the IL-1 injection. The cellular infiltrate was not reduced at all if the IL-1 receptor was injected 2 hours after the IL-1. The activity of the soluble receptor deserves further study as a therapeutic modality for inflammatory eye disease.