• The present, masked, controlled study compares the therapeutic efficacy of guttate 3% vidarabine, 0.1% idoxuridine, and 1% trifluridine in herpes simplex keratouveitis in rabbits. Vidarabine, whether given every hour, every two hours, or every three hours was significantly better than controls but significantly worse than idoxuridine or trifluridine. Trifluridine and idoxuridine were not significantly different from each other. Viral cultures taken at the end of the six-day treatment period were positive in the majority of all treatment groups except for the trifluridine group, which was 100% negative. Although previous studies have shown that vidarabine is very effective as an antiviral ointment, vidarabine drops are not as effective as guttate idoxuridine or trifluridine.