Complications arising from the procedure to produce denervation of the cornea have made experiments on the trophic role of trigeminal nerve difficult. In this study, controlled lesions of the rabbit trigeminal ganglion were produced by radio-frequency thermocoagulation, delivered by a needle electrode inserted through the soft palate of the mouth. The advantages of the procedure were low mortality (less than 5%), permanent destruction of sensory neurons, and absence of spurious ocular effects. Two lesion sizes were reliably produced: 1. The smaller circumscribed lesion resulted in loss of corneal sensitivity, but preserved spontaneous blinking. 2. The larger lesion extended across the ganglion, abolished corneal sensation and spontaneous blink activity.