It is well known that people with idiopathic trigeminal neuralgia sometimes have teeth unnecessarily extracted. It is less well known that pain which seems to be due to idiopathic trigeminal neuralgia is occasionally due to dental causes. For this reason it is suggested that such cases should be given very careful dental and oral examination before the commencement of drug therapy or surgery. Such an examination must be meticulous and may be tedious as well as time consuming. It should therefore be done by a dentist who is specially interested in pain and who is preferably associated with a centre for pain relief. A few cases may then have their pain relieved by such procedures as fillings, extractions or occlusal adjustment. In all cases the neurologist or neurosurgeon will face his responsibility more secure in the knowledge that all possible peripheral causes have been eliminated. Moreover, patients with idiopathic trigeminal neuralgia may have difficulty maintaining a satisfactory standard of oral hygiene, both before and after treatment. They should therefore have careful attention paid to this as soon as possible.