We treated 25 patients with dendritic keratitis with debridement and 3% acyclovir ointment and another 25 with acyclovir alone. The patients were randomly assigned to the two treatment groups. There were only minimal adverse effects in both groups. The combination of debridement and acyclovir produced a significantly more rapid healing rate than did acyclovir alone. Factors associated with prolonged healing time were duration of symptoms (longer than one week), length of the epithelial defect (greater than 4 mm), proximity of the defect to the corneoscleral limbus (less than 2 mm), and the presence of stromal inflammation.