The effects of fluorescein and Richardson''s stain on corneal epithelial wound healing were compared in eyes of rabbits whose corneas had the epithelium removed by scraping or by n-heptanol. One eye of each rabbit was stained with fluorescein and the other eye was stained with Richardson''s stain at intervals throughout the healing process, and the wounds were photographed for planimetry and determination of re-epithelialization rate. Corneal thickness was also measured throughout the re-epithelialization. Richardson''s stain, as compared with fluorescein, decreases re-epithelialization rate, delays wound closure and slows the return of the edematous cornea to normal thickness. Fluorescein rather than Richardson''s stain should be used to stain epithelial defects in corneal wound healing studies and in the evaluation of the corneal toxicity of chemical agents.