THE OCCURRENCE of trigeminal neuralgia and multiple sclerosis in the same individual is so uncommon that the problem might be considered inconsequential were it not for the fact that it raises several interesting questions. This combination of diseases occurs more frequently than can be accounted for by mere chance. It is commonly stated that in patients with both diseases trigeminal neuralgia appears at an earlier age and is more often bilateral than in those patients having trigeminal neuralgia alone. Often, these statements are made without supporting evidence, or the evidence adduced is insubstantial. This combination of diseases has been cited as evidence for the contention that the pain of trigeminal neuralgia is of "central" origin. Postmortem studies of subjects who had been afflicted with both diseases have yielded interesting but inconclusive results.1-6 The incidence of multiple sclerosis in patients with trigeminal neuralgia has varied greatly in different