The retinal toxicity of daunomycin, a drug that effectively suppresses experimental proliferative vitreoretinopathy (PVR), was studied in the rabbit by clinical examination, electroretinography (ERG), light microscopy, and electron microscopy. Although no toxicity was observed at the therapeutically effective dose of 10 nmol per eye, the safety margin is too small to recommend this drug for therapy of proliferative vitreoretinopathy in man.