A 9-mm perforating corneal wound was created in one eye of New Zealand albino rabbits, sutured, and treated with mouse-derived epidermal growth factor (1 mg/L), human-derived epidermal growth factor (1.0 mg/L to 100 mg/L), or buffered saline, instilled once, twice, or four times daily. Both mouse-derived epidermal growth factor and human-derived epidermal growth factor significantly increased the tensile strength of full-thickness corneal wounds after 9 days of topical therapy. For human-derived epidermal growth factor, a concentration of 10 mg/L administered twice daily produced the maximal effect. An increase in either the concentration of epidermal growth factor or its frequency of administration failed to induce a further increase in wound strength. Indeed, at a concentration of 100 mg/L, human-derived epidermal growth factor appeared to lose its ability to accelerate healing of full-thickness corneal wounds.