The slowed healing rates observed by some investigators may he caused by vehicles or preservatives in the antimicrobials preparations tested. To determine whether antimicrobials directly inhibit corneal epithelial wound healing, we cultured blocks of the rabhit cornea in media containing various concentrations of antibiotics or antimicrobials (at 1, 10, or 100μg/ml); after 24 hours, we measured the distance of epithelium that had migrated down the side of each block. The higher concentrations of fluoroquinolones (ofloxacin; 74±5.8 % of control at 100μg/ml, p<0.05, ciprofloxacin; 4.4±1.5 %1 of control at 100μg/ml, p<0. 01, or norfloxacin; 71±7.0 % at 10μg/ml, p<0.01, and 1.5±0.4 % of control at 100μg/ml, p<0.01) and the highest concentrations of peptides (polymyxin B; 64±3.0 % of control at 100μg/ml, p<0.01, or colistin; 67±5.7 % of control at 100μg/mI, p<0.01) or fosfomycin (79±6.2 % of control at 100μg/ml, p<0.05) had an inhibitory effect on corneal epithelial migration. Among aminoglycosides tested, sisomicin (85±10.0 % of control, not significant), dibekacin (76±11.6 % of control, p<0.05) and streptomycin (77±9.4 %, of control, not significant) were inhibitory at 100μg/ml, but tobramycin had no effect. Penicillins (aspoxicillin, subenicillin or ampicillin), cephalosporins (cefmenoxime or cefminox), oxytetracycline, erythromycin and chloramphenicol did not affect epithelial migration at all. These results demonstrate that some antimicrobials are inhibitory at high concentrations, but penicillins, cephalosporins, oxytetracycline, erythromycin or chloramphenicol has no inhibitory effect on corneal epithelial migration.