Patients (30) with tic douloureux underwent treatment by percutaneous retrogasserian glycerol injection (PRGI). All patients had symptomatic trigeminal neuralgia refractory to medical therapy. Fifteen had recurrent tic after 1-4 prior operations. The technique was simple to perform and required no intraoperative physiological testing or short-acting barbiturate supplementation during transovale placement of a spinal needle in the trigeminal cistern of Meckel''s cave. Precise placement of small volumes (0.15-0.35 ml) of sterile glycerol was ensured by first demonstrating the anatomy of the trigeminal cistern using metrizamide. Overall, 23 patients have remained pain-free 5-12 mo. after treatment. Patients (19) had no change in facial sensation after injection. Treatment by PRGI is a valid alternative therapy for tic douloureux, with the additional benefit of a much reduced incidence of facial sensory loss when compared with differential thermal rhizotomy by a radiofrequency-induced lesion technique. Facial deafferentation is not mandatory for successful percutaneous treatment of tic douloureux.