The effect of topically administrated indomethacin was studied in rabbits on an experimentally provoked inflammatory keratitis. Intrastromal injection with horse serum induced in the cornea a ring-shaped infiltration with leukocytes and neovascularization-Indomethacin was given as eye drops three times daily during the experiment. In the indomethacin treated eyes leukocyte infiltration was prolonged but not the concomitant neovascularization. The potentiation of the leukocyte response may be due to a facilitation of chemotactic lipoxygenase products.