In a study of the corneal toxicity of some commonly used presurgical skin antiseptics, we used biomicroscopy, corneal pachymetry, healing studies, and electron microscopy to compare tincture of iodine (2% iodine, 2.35% sodium iodine, and 46% ethanol), Hibiclens (4% chlorhexidine and 4% isopropyl alcohol with detergent), pHisoHex (3% hexachlorophene and detergent), Lavacol (70% ethanol), 7.5% povidone iodine scrub (with a detergent), and 10% povidone iodine solution (without a detergent) in rabbits. Five minutes after application, moderate corneal epithelial edema was noted in all groups except the saline control group. After three hours there was marked corneal de-epithelialization, conjunctival chemosis, and anterior stromal edema in all groups except those treated with 10% povidone iodine solution and 0.9% sodium chloride. After one week all corneas had returned to normal. Accidental instillation of 7.5% povidone iodine scrub into the tear film of a 33-year-old man resulted in almost immediate chemical chemosis despite prompt irrigation, demonstrating the corneal toxicity of this substance. These results indicated that a 10% povidone iodine solution without detergent causes minimal corneal toxicity whereas the other presurgical skin antiseptics tested are toxic to the cornea.