A retrospective analysis of 175 patients who were suffering from trigeminal neuralgia was done. We found 21 cases (12.0%) of abnormal findings including brain tumors and cerebrovascular disease on brain MRI. All patients were transferred to department of neurosurgery for operation. Among them, 7 patients refused or gave up operation and received nerve blocks with pure alcohol. Their MRI findings were meningioma, arachnoid cyst, arteriovenous malformation, venous angioma, and frontal sinus cancer This study demonstrates that peripheral nerve block or trigeminal nerve block with pure alcohol would be possible in case of elderly patients, patients who have poor general condition, patients who refuse operation, and brain tumor or cerebrovascular disease which located in dangerous area to be operated.