Free-radical-mediated tissue damage is thought to be involved in a multitude of ophthalmic pathologies. Therefore, drugs that scavenge free radicals may find wide clinical application. A new chemical class of antiinflammatory agents, the 21-aminosteroids, has been developed as free radical scavengers. These agents are thought to inhibit lipid peroxidation and prevent the release of free arachidonic acid from injured cell membranes. In the present study, we investigated the intraocular toxicity of one of the 21-aminosteroids, U75412E. Intravitreal doses of up to 0.1 mg of U75412E were nontoxic to rabbit ocular tissues.