SOD and other active oxygen inhibitors are directly applied in combination with a barrier material at local sites of tissue injury to prevent or decrease formation of adhesions and undesirable proliferation of cells. Preferred barrier materials are polymeric hydrogels providing controlled release of AOI which are directly applied to the afflicted tissue. Examples demonstrate the effects of SOD on pelvic adhesions in the rat when administered by intraperitoneal (I.P.) bolus and by localized sustained release from a topically applied hydrogel system.