The treatment of neuralgia which occurs during and following herpes zoster ophthalmicus is often unsatisfactory. Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide) is a drug which depletes substance P and may be effective in inhibiting pain. We utilized topical capsaicin to the affected dermatome five times daily for 4 weeks in 6 patients with acute and post herpetic neuralgia. In four cases pain was markedly relieved and narcotic medications were either discontinued or significantly reduced. In two cases, pain was not reduced. Four patients had side effects including burning sensation at the site of the drug administration (4 cases), dermatitis as a result of overuse of the drug (2 cases) and hyperesthesia (1 case). Our results suggest that capsaicin may be a useful therapy for the alleviation of pain in some individuals with herpes zoster ophthalmicus. However, controlled studies are needed to establish these results.